Polymers

Research

17 pages, 10273 KiB

Open AccessArticle

A Novel Fused SiO₂ and h-BN Modified Quartz Fiber/Benzoxazine Resin Ceramizable Composite with Excellent Flexural Strength and Ablation Resistance

by Zongyi Deng, Yunfei Lv, Minxian Shi, Zhixiong Huang and Wenchao Huang

Polymers 2023, 15(22), 4430; https://doi.org/10.3390/polym15224430 - 16 Nov 2023

Cited by 2 | Viewed by 1804

Abstract

Hypersonic vehicles encounter hostile service environments of thermal/mechanical/chemical coupling, so thermal protection materials are crucial and essential. Ceramizable composites have recently attracted intensive interest due to their ability to provide large-area thermal protection for hypersonic vehicles. In this work, a novel ceramizable composite [...] Read more.

Hypersonic vehicles encounter hostile service environments of thermal/mechanical/chemical coupling, so thermal protection materials are crucial and essential. Ceramizable composites have recently attracted intensive interest due to their ability to provide large-area thermal protection for hypersonic vehicles. In this work, a novel ceramizable composite of quartz fiber/benzoxazine resin modified with fused SiO₂ and h-BN was fabricated using a prepreg compression molding technique. The effects of the fused SiO₂ and h-BN contents on the thermal, mechanical, and ablative properties of the ceramizable composite were systematically investigated. The ceramizable composite with an optimized amount of fused SiO₂ and h-BN exhibited superb thermal stability, with a peak degradation temperature and residue yield at 1400 °C of 533.2 °C and 71.5%, respectively. Moreover, the modified ceramizable composite exhibited excellent load-bearing capacity with a flexural strength of 402.2 MPa and superior ablation resistance with a linear ablation rate of 0.0147 mm/s at a heat flux of 4.2 MW/m², which was significantly better than the pristine quartz fiber/benzoxazine resin composite. In addition, possible ablation mechanisms were revealed based on the microstructure analysis, phase transformation, chemical bonding states, and the degree of graphitization of the ceramized products. The readily oxidized pyrolytic carbon (PyC) and the SiO₂ with a relatively low melting point were converted in situ into refractory carbide. Thus, a robust thermal protective barrier with SiC as the skeleton and borosilicate glass as the matrix protected the composite from severe thermochemical erosion and thermomechanical denudation. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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14 pages, 7916 KiB

Open AccessArticle

Influence of Isothermal Aging on Microstructure and Shear Property of Novel Epoxy Composite SAC305 Solder Joints

by Peng Zhang, Songbai Xue, Lu Liu, Jianhao Wang, Hiroaki Tatsumi and Hiroshi Nishikawa

Polymers 2023, 15(20), 4168; https://doi.org/10.3390/polym15204168 - 20 Oct 2023

Cited by 5 | Viewed by 1954

Abstract

With the rapid iteration of microsystem integrated technology, the miniaturization of electronic devices requires packaging materials with higher reliability. In this work, the microstructure evolution and mechanical properties of novel epoxy composite SAC305 solder joints were studied after isothermal aging to evaluate the [...] Read more.

With the rapid iteration of microsystem integrated technology, the miniaturization of electronic devices requires packaging materials with higher reliability. In this work, the microstructure evolution and mechanical properties of novel epoxy composite SAC305 solder joints were studied after isothermal aging to evaluate the enhanced effect of epoxy addition. The thickness variation and morphological evolution of the interfacial layer were analyzed. The results showed that, as the aging time was prolonged, the Cu₆Sn₅ interfacial layer remarkably coarsened and Cu₃Sn compounds formed between the Cu₆Sn₅ layer and Cu pad due to the continuous atomic diffusion. Compared with the monolithic joint, the epoxy composite SAC305 joints had a lower overall IMC growth rate during aging, closely related to the initial morphologies of the interfacial layers. The shear test results showed an apparent decrease in the shear forces of all the solder joints as the aging time increased. Nevertheless, because of the extra mechanical support provided by the epoxy layer, the epoxy composite joints demonstrated notably enhanced mechanical properties. After 1000 h aging treatment, the shear force of SAC305 joints containing 8 wt.% epoxy was 26.28 N, showing a 24.08% increase over the monolithic joint. Cu-Sn IMCs were detected on the shear fracture of the monolithic joint after 1000 h aging, indicating the fracture occurred near the interface and displayed a ductile/brittle mixed fracture. Concerning the epoxy composite joints, cracks were still initiated and extended within the solder bulk, demonstrating a noticeable enhancement in ductility due to the addition of epoxy. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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15 pages, 4021 KiB

Open AccessArticle

Effects of Short-Term Exposure of Chloramine-T Solution on the Characteristics of Light-Cured and Chemical-Cured Adhesives

by Yunqing Liu, Norihito Sakaguchi, Masahiro Iijima, Md Refat Readul Islam, Jiayuan Zhang, Rafiqul Islam, Monica Yamauti, Hidehiko Sano and Atsushi Tomokiyo

Polymers 2023, 15(19), 3995; https://doi.org/10.3390/polym15193995 - 5 Oct 2023

Cited by 1 | Viewed by 2288

Abstract

This study evaluated the effect of a 0.5% chloramine T solution on a chemical-cured universal adhesive by comparing the light-cured, one-step, self-etch adhesive for the bonding performance, mechanical properties, and resin–dentin interfacial characteristics. Caries-free human molars were randomly assigned into eight groups based [...] Read more.

This study evaluated the effect of a 0.5% chloramine T solution on a chemical-cured universal adhesive by comparing the light-cured, one-step, self-etch adhesive for the bonding performance, mechanical properties, and resin–dentin interfacial characteristics. Caries-free human molars were randomly assigned into eight groups based on the bonding systems employed (Bond Force II, BF and Bondmer Lightless, BL), the immersion solutions used before bonding (0.5% chloramine T solution and distilled water), and the immersion durations (5 and 60 min). Microtensile bond strength (μTBS), nanoleakage evaluation, and nanoindentation tests were performed, and the surface morphology of the resin–dentin interface was examined using a focus ion beam/scanning ion microscopy system. Immersion in chloramine-T for 5 min significantly decreased the μTBS of Bondmer Lightless (from 22.62 to 12.87 MPa) compared with that in distilled water. Moreover, there was also a decreasing trend after immersing in chloramine-T for 60 min (from 19.11 to 13.93 MPa). Chloramine T was found to have no effect on the hardness, elastic modulus, or morphological characteristics of the ion-beam milled resin–dentin interfacial surfaces in the tested adhesives, suggesting that chloramine T might reduce the bond strength by interfering with the interaction and the sealing between the adhesive resin and dentin in the chemical-cured universal adhesive, albeit without affecting the mechanical properties. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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18 pages, 21621 KiB

Open AccessArticle

Thermal and Colorimetric Parameter Evaluation of Thermally Aged Materials: A Study of Diglycidyl Ether of Bisphenol A/Triethylenetetramine System and Fique Fabric-Reinforced Epoxy Composites

by Michelle Souza Oliveira, Artur Camposo Pereira, Henry Alonso Colorado, Natalin Michele Meliande, Juliana dos Santos Carneiro da Cunha, André Ben-Hur da Silva Figueiredo and Sergio Neves Monteiro

Polymers 2023, 15(18), 3761; https://doi.org/10.3390/polym15183761 - 14 Sep 2023

Cited by 1 | Viewed by 1344

Abstract

The main modifications of thermal and colorimetric parameters after thermal aging of DGEBA/TETA system (plain epoxy) and fique-fiber woven fabric-reinforced epoxy composites are described. As a preliminary study, thermal analysis was carried out on epoxy matrix composites reinforced with 15, 30, 40 and [...] Read more.

The main modifications of thermal and colorimetric parameters after thermal aging of DGEBA/TETA system (plain epoxy) and fique-fiber woven fabric-reinforced epoxy composites are described. As a preliminary study, thermal analysis was carried out on epoxy matrix composites reinforced with 15, 30, 40 and 50% fique-fiber woven fabric. After this previous analysis, the 40% composite was chosen to be thermally aged, at 170 °C. Three exposure times were considered, namely, 0, 72, 120 and 240 h. Samples were studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and colorimetry analysis. Significant color changes were observed after thermal aging combined with oxidation. It was also found that the thermal behavior of the plain epoxy showed greater resistance after thermal exposure. By contrast, the composites were more sensitive to temperature variations as a result of thermal stresses induced between fique fibers and the epoxy matrix. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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18 pages, 7060 KiB

Open AccessArticle

A Study of Isosorbide Synthesis from Sorbitol for Material Applications Using Isosorbide Dimethacrylate for Enhancement of Bio-Based Resins

by Vojtěch Jašek, Jan Fučík, Jiří Krhut, Ludmila Mravcova, Silvestr Figalla and Radek Přikryl

Polymers 2023, 15(17), 3640; https://doi.org/10.3390/polym15173640 - 4 Sep 2023

Cited by 6 | Viewed by 3165

Abstract

Bio-based cross-linkers can fulfill the role of enhancing additives in bio-sourced curable materials that do not compare with artificial resin precursors. Isosorbide dimethacrylate (ISDMMA) synthesized from isosorbide (ISD) can serve as a cross-linker from renewable sources. Isosorbide is a bicyclic carbon molecule produced [...] Read more.

Bio-based cross-linkers can fulfill the role of enhancing additives in bio-sourced curable materials that do not compare with artificial resin precursors. Isosorbide dimethacrylate (ISDMMA) synthesized from isosorbide (ISD) can serve as a cross-linker from renewable sources. Isosorbide is a bicyclic carbon molecule produced by the reaction modification of sorbitol and the optimal conditions of this reaction were studied in this work. The reaction temperature of 130 °C and 1% w/w amount of para-toluenesulfonic acid (p-TSA) were determined as optimal and resulted in a yield of 81.9%. Isosorbide dimethacrylate was synthesized via nucleophilic substitution with methacrylic anhydride (MAA) with the conversion of 94.1% of anhydride. Formed ISD and ISDMMA were characterized via multiple verification methods (FT-IR, MS, ¹H NMR, and XRD). Differential scanning calorimetry (DSC) proved the curability of ISDMMA (activation energy E_a of 146.2 kJ/mol) and the heat-resistant index of ISDMMA (T_s reaching value of 168.9) was determined using thermogravimetric analysis (TGA). Characterized ISDMMA was added to the precursor mixture containing methacrylated alkyl 3-hydroxybutyrates (methyl ester M3HBMMA and ethyl ester E3HBMMA), and the mixtures were cured via photo-initiation. The amount of ISDMMA cross-linker increased all measured parameters obtained via dynamic mechanical analysis (DMA), such as storage modulus (E’) and glass transition temperature (T_g), and the calculated cross-linking densities (ν_e). Therefore, the enhancement influence of bio-based ISDMMA on resins from renewable sources was confirmed. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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12 pages, 2608 KiB

Open AccessArticle

Synthesis and Characterization of an Environmentally Friendly Phenol–Formaldehyde Resin Modified with Waste Plant Protein

by Hanyin Li, Sen Wang, Xiang Zhang, Hao Wu, Yujie Wang, Na Zhou, Zijie Zhao, Chao Wang, Xiaofan Zhang, Xian Wang and Cheng Li

Polymers 2023, 15(13), 2975; https://doi.org/10.3390/polym15132975 - 7 Jul 2023

Cited by 8 | Viewed by 2061

Abstract

To develop a lower-cost, excellent-performance, and environmentally friendly phenol–formaldehyde (PF) resin, soybean meal was used to modify PF resin, and soybean meal–phenol–formaldehyde (SMPF) resins were prepared. This reveals the effect of soybean meal on the structural, bonding, and curing properties of PF resin, [...] Read more.

To develop a lower-cost, excellent-performance, and environmentally friendly phenol–formaldehyde (PF) resin, soybean meal was used to modify PF resin, and soybean meal–phenol–formaldehyde (SMPF) resins were prepared. This reveals the effect of soybean meal on the structural, bonding, and curing properties of PF resin, which are very important for its applications in the wood industry. The resins’ physicochemical properties and curing performance were investigated, showing that SMPF resins have higher curing temperatures than PF resin. The Fourier transform infrared spectroscopy results indicated that a cross-linking reaction occurred between the amino groups of soybean protein and the hydroxymethyl phenol. Moreover, with the addition of soybean meal, the viscosity of SMPF increased while the gel time decreased. It is worth mentioning that SMPF-2 resin has favorable viscosity, short gel time, low curing temperature (135.78 °C), and high water resistance and bonding strength (1.01 MPa). Finally, all the plywoods bonded with SMPF resins have good water resistance and bonding strength, which could meet the standard (GB/T 17657-2013, type I) for plywood. The optimized SMPF resins showed the potential for application to partially replace PF resin in the wood industry. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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15 pages, 4016 KiB

Open AccessArticle

Bisphenol A Diglycidyl Ether-Primary Amine Cooligomer-poly(ε-caprolactone) Networks: Synthesis and Characterization

by Katalin Czifrák, Csilla Lakatos, Gabriella Szabó, Bence Vadkerti, Lajos Daróczi, Miklós Zsuga and Sándor Kéki

Polymers 2023, 15(13), 2937; https://doi.org/10.3390/polym15132937 - 3 Jul 2023

Cited by 2 | Viewed by 2741

Abstract

In this work, the preparation and systematic investigation of cross-linked polyurethane-epoxy (PU-EP) polymer systems are reported. The PU-EP polymers were prepared using a reaction of isocyanate (NCO)-terminated PU-prepolymer with diglycidyl ether of bisphenol A (DGEBA)-amine cooligomer. The oligomerization of DGEBA was carried out [...] Read more.

In this work, the preparation and systematic investigation of cross-linked polyurethane-epoxy (PU-EP) polymer systems are reported. The PU-EP polymers were prepared using a reaction of isocyanate (NCO)-terminated PU-prepolymer with diglycidyl ether of bisphenol A (DGEBA)-amine cooligomer. The oligomerization of DGEBA was carried out by adding furfurylamine (FA) or ethanolamine (EA), resulting in DGEBA-amine cooligomers. For the synthesis of NCO-terminated PU-prepolymer, poly(ε-caprolactone)diol (PCD) (M_n = 2 kg/mol) and 1,6-hexamethylene diisocyanate (HDI) were used. The cross-linking was achieved by adding DGEBA-amine cooligomer to PU-prepolymer, in which the obtained urethane bonds, due to the presence of free hydroxil groups in the activated DGEBA, served as netpoints. During cross-linking, ethanolamine provides an additional free hydroxyl group for the formation of a new urethane bond, while furfurylamine can serve as a thermoreversible coupling element (e.g., Diels–Alder adduct). The PU-EP networks were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) and scanning electron microscopy (SEM). The DMA curves of some PU-EPs (depending on the compositions and the synthetic method) revealed a plateau-like region above the melting temperature (T_m) of PCD, confirming the presence of a cross-linked structure. This property resulted in a shape memory (SM) behavior for these samples, which can be fine-tuned in the presence of furfurylamine through the formation of additional thermoreversible bonds (e.g., Diels–Alder adduct). Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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17 pages, 5368 KiB

Open AccessArticle

Efficient and Sustainable Bidentate Amines-Functionalized Resins for Removing Ag⁺, Cu²⁺, Pb^2+, and Fe³⁺ from Water

by Ana-Laura Villa-Reyna, Milagros Aguilar-Martínez, Adrián Ochoa-Terán, Hisila Santacruz-Ortega, Mario-Alberto Leyva-Peralta, Judas-Tadeo Vargas-Durazo, Moisés I. Salazar-Gastelum, José García-Elías and Juan-Carlos Gálvez-Ruiz

Polymers 2023, 15(13), 2778; https://doi.org/10.3390/polym15132778 - 22 Jun 2023

Cited by 1 | Viewed by 1763

Abstract

We evaluate the effectiveness of chelating resins (CR) derived from Merrifield resin (MR) and 1,2-phenylenediamine (PDA), 2,2’-dipyridylamine (DPA), and 2-(aminomethyl)pyridine (AMP) as adsorbent dosimeters for Ag⁺, Cu²⁺, Fe³⁺, and Pb²⁺ cations from water under competitive and [...] Read more.

We evaluate the effectiveness of chelating resins (CR) derived from Merrifield resin (MR) and 1,2-phenylenediamine (PDA), 2,2’-dipyridylamine (DPA), and 2-(aminomethyl)pyridine (AMP) as adsorbent dosimeters for Ag⁺, Cu²⁺, Fe³⁺, and Pb²⁺ cations from water under competitive and noncompetitive conditions. MR-PDA, MR-DPA, and MR-AMP were obtained in a 95–97% yield and characterized by IR, fluorescence, and SEM. The ability of CRs as adsorbents was determined by batch and flow procedures. MR-PDA showed a batch adsorption capacity order of Fe³⁺ (29.8 mg/g) > Ag⁺ (2.7 mg/g) > Pb²⁺ (2.6 mg/g) at pH 3.4. The flow adsorption showed affinity towards the Ag⁺ cation at pH 7 (18.4 mg/g) and a reusability of 10 cycles. In MR-DPA, the batch adsorption capacity order was Ag⁺ (9.1 mg/g) > Pb²⁺ (8.2 mg/g) > Cu²⁺ (3.5 mg/g) at pH 5. The flow adsorption showed affinity to the Cu²⁺ cation at pH 5 (2.2 mg/g) and a reuse of five cycles. In MR-AMP, the batch adsorption capacity was Ag⁺ (17.1 mg/g) at pH 3.4. The flow adsorption showed affinity to the Fe³⁺ cation at pH 2 (4.3 mg/g) and a reuse of three cycles. The three synthesized and reusable CRs have potential as adsorbents for Ag⁺, Cu²⁺, Fe³⁺, and Pb²⁺ cations and showed versatility in metal removal for water treatment. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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11 pages, 1552 KiB

Open AccessArticle

Determination of the Attenuation Coefficients of Epoxy Resin with Carbopol Polymer as a Breast Phantom Material at Low Photon Energy Range

by Mohammad Marashdeh and Muthanna Abdulkarim

Polymers 2023, 15(12), 2645; https://doi.org/10.3390/polym15122645 - 11 Jun 2023

Cited by 8 | Viewed by 2288

Abstract

Six different composites of epoxy resin and Carbopol 974p polymer were prepared based on Carbopol 974p polymer concentrations of 0%, 5%, 10%, 15%, 20%, and 25%. The linear and mass attenuation coefficients, Half Value Layer (HVL), and mean free path (MFP) of these [...] Read more.

Six different composites of epoxy resin and Carbopol 974p polymer were prepared based on Carbopol 974p polymer concentrations of 0%, 5%, 10%, 15%, 20%, and 25%. The linear and mass attenuation coefficients, Half Value Layer (HVL), and mean free path (MFP) of these composites were determined using single-beam photon transmission in the energy range between 16.65 keV and 25.21 keV. This was carried out by determining the attenuation of k_a1 X-ray fluorescent (XRF) photons from niobium, molybdenum, palladium, silver, and tin targets. The results were compared with theoretical values of three types of breast material (Breast 1, Breast 2, Breast 3) and Perspex, which was calculated using a XCOM computer program. The results show that there were no significant differences in the attenuation coefficient values after the consequent Carbopol additions. Moreover, it was found that the mass attenuation coefficients of all tested composites were close to those of Perspex and the values for Breast 3. The HVL and MFP results showed that the E25 sample is closer to the results of the Perspex material with differences of (0.53–1.15%) and (0.51–1.20%), respectively. In addition, the densities of the fabricated samples were in the range of 1.102–1.170 g/cm³, which is in the range of human breast density. A computed tomography (CT) scanner was used to investigate the CT number values for the fabricated samples. The CT numbers of all samples were in the range of human breast tissue (24.53–40.28 HU). Based on these findings, the fabricated epoxy–Carbopol polymer is a good candidate for use as a breast phantom material. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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11 pages, 708 KiB

Open AccessArticle

Understanding the Mechanical, Surface, and Color Behavior of Oral Bioactive Prosthetic Polymers under Biodegradation Processes

by Cristina B. Neves, Joana Costa, Jaime Portugal and Ana F. Bettencourt

Polymers 2023, 15(11), 2549; https://doi.org/10.3390/polym15112549 - 31 May 2023

Cited by 4 | Viewed by 1491

Abstract

Changes in the properties of resin-based polymers exposed to the oral environment can emerge when chlorhexidine (CHX) is incorporated to develop bioactive systems for treating denture stomatitis. Three reline resins loaded with CHX were prepared: 2.5 wt% in Kooliner (K), 5 wt% in [...] Read more.

Changes in the properties of resin-based polymers exposed to the oral environment can emerge when chlorhexidine (CHX) is incorporated to develop bioactive systems for treating denture stomatitis. Three reline resins loaded with CHX were prepared: 2.5 wt% in Kooliner (K), 5 wt% in Ufi Gel Hard (UFI), and Probase Cold (PC). A total of 60 specimens were submitted to physical aging (1000 cycles of thermal fluctuations, 5–55 °C) or chemical aging (28 days of pH fluctuations in artificial saliva, 6 h at pH = 3, 18 h at pH = 7). Knoop microhardness (30 s, 98 mN), 3-point flexural strength (5 mm/min), and surface energy were tested. Color changes (ΔE) were determined using the CIELab system. Data were submitted to non-parametric tests (α = 0.05). After aging, bioactive K and UFI specimens were not different from the controls (resins without CHX) in mechanical and surface properties. Thermally aged CHX-loaded PC specimens showed decreased microhardness and flexural strength but not under adequate levels for function. The color change was observed in all CHX-loaded specimens that underwent chemical aging. The long-term use of CHX bioactive systems based on reline resins generally does not impair removable dentures’ proper mechanical and aesthetic functions. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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14 pages, 6066 KiB

Open AccessArticle

NMR and GPC Analysis of Alkyd Resins: Influence of Synthesis Method, Vegetable Oil and Polyol Content

by Antonella Hadzich, Santiago Flores, Ashley E. Masucci, Enrique D. Gomez and G. Alexander Groß

Polymers 2023, 15(9), 1993; https://doi.org/10.3390/polym15091993 - 23 Apr 2023

Cited by 6 | Viewed by 3919

Abstract

Alkyd resins are oil-based polymers that have been widely used for generations in the surface coating industry and beyond. Characterization of these resins is of high importance to understand the influence of its components on its behavior, compatibility with other resins, and final [...] Read more.

Alkyd resins are oil-based polymers that have been widely used for generations in the surface coating industry and beyond. Characterization of these resins is of high importance to understand the influence of its components on its behavior, compatibility with other resins, and final quality to ensure high durability. Here, NMR spectroscopy and GPC were used for characterizing differences in the chemical structure, molecular distribution, and dispersity between oil-based and fatty acid-based alkyd polymers made from sacha inchi and linseed oils. Sancha inchi (Plukentia volubilis L.) is a fruit-bearing plant native to South America and the Caribbean, and has a rich unsaturated fatty acid content. The effect of vegetable oil and polyol selection on the synthesis of alkyd resins for coating applications was analyzed. The influence of two different synthesis methods, monoglyceride and fatty acid processes, was also compared. Important structural differences were observed using NMR: one-dimensional spectra revealed the degree of unsaturated fatty acid chains along the polyester backbone, whereas, 2D NMR experiments facilitated chemical shift assignments of all signals. GPC analysis suggested that alkyd resins with homogeneous and high molecular weights can be obtained with the fatty acid process, and that resins containing pentaerythritol may have uniform chain lengths. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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13 pages, 1975 KiB

Open AccessArticle

Influence of Biochar and Bio-Oil Loading on the Properties of Epoxy Resin Composites

by Pamela Hidalgo, Luis Salgado, Nayadeth Ibacache and Renato Hunter

Polymers 2023, 15(8), 1895; https://doi.org/10.3390/polym15081895 - 15 Apr 2023

Cited by 8 | Viewed by 2438

Abstract

In this study, we evaluated the use of bio-oil and biochar on epoxy resin. Bio-oil and biochar were obtained from the pyrolysis of wheat straw and hazelnut hull biomass. A range of bio-oil and biochar proportions on the epoxy resin properties and the [...] Read more.

In this study, we evaluated the use of bio-oil and biochar on epoxy resin. Bio-oil and biochar were obtained from the pyrolysis of wheat straw and hazelnut hull biomass. A range of bio-oil and biochar proportions on the epoxy resin properties and the effect of their substitution were investigated. TGA curves showed improved thermal stability for degradation temperature at the 5% (T5%), 10% (T10%), and 50% (T50%) weight losses on bioepoxy blends with the incorporation of bio-oil and biochar with respect to neat resin. However, decreases in the maximum mass loss rate temperature (T_max) and the onset of thermal degradation (T_onset) were obtained. Raman characterization showed that the degree of reticulation with the addition of bio-oil and biochar does not significantly affect chemical curing. The mechanical properties were improved when bio-oil and biochar were incorporated into the epoxy resin. All bio-based epoxy blends showed a large increase in Young’s modulus and tensile strength with respect to neat resin. Young’s modulus was approximately 1955.90 to 3982.05 MPa, and the tensile strength was between 8.73 and 13.58 MPa for bio-based blends of wheat straw. Instead, in bio-based blends of hazelnut hulls, Young´s modulus was 3060.02 to 3957.84 MPa, and tensile strength was 4.11 to 18.11 Mpa. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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20 pages, 6800 KiB

Open AccessArticle

Nonlinear Mechanical Property of 3D Braided Composites with Multi-Types Micro-Distortion: A Quantitative Evaluation

by Junjun Zhai, Xiangxia Kong, Luchen Wang, Shi Yan, Lili Jiang and Zhiwei Cai

Polymers 2023, 15(6), 1428; https://doi.org/10.3390/polym15061428 - 14 Mar 2023

Cited by 1 | Viewed by 1719

Abstract

A new alternative calculation procedure is developed to quantify the effect of yarn distortion characteristics on the mechanical properties of three-dimensional (3D) braided carbon/resin composites. Firstly, the multi-type yarn distortion characteristics factors including path, cross-section shape and cross-section torsion effects are described based [...] Read more.

A new alternative calculation procedure is developed to quantify the effect of yarn distortion characteristics on the mechanical properties of three-dimensional (3D) braided carbon/resin composites. Firstly, the multi-type yarn distortion characteristics factors including path, cross-section shape and cross-section torsion effects are described based on the stochastic theory. Then, the multiphase finite element method is employed to overcome the complex discretization in traditional numerical analysis, and the parametric studies including multi-type yarn distortion and different braided geometrical parameters on the resulting mechanical properties are performed. It is shown that the proposed procedure can simultaneously capture the yarn path and cross-section distortion characteristics caused by the mutual squeeze of component materials, which is difficult to characterize by experimental methods. In addition, it is found that even small distortions of yarn may significantly affect the mechanical properties for 3D braided composites, and the 3D braided composites with different braiding geometric parameters will show different sensitivity to the distortion characteristics factors of yarn. The procedure, which could be implemented into commercial finite element codes, is an efficient tool for the design and structural optimization analysis of a heterogeneous material with anisotropic properties or complex geometries. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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12 pages, 1452 KiB

Open AccessArticle

In Vitro Color Stability Evaluation of Three Polished and Unpolished Nanohybrid Resin Composites Immersed in a 0.12% Chlorhexidine-Based Mouthwash at Different Times

by Reyna Allccahuaman-Avalos, Ramín Medina-Sánchez, Leonor Castro-Ramirez, Marysela Ladera-Castañeda, Luis Cervantes-Ganoza, Reynaldo Martínez-Campos, Fredy Solís-Dante, Ana Aliaga-Mariñas, Arturo Verástegui-Sandoval and César Cayo-Rojas

Polymers 2023, 15(6), 1339; https://doi.org/10.3390/polym15061339 - 7 Mar 2023

Cited by 3 | Viewed by 2669

Abstract

The use of chlorhexidine-based mouthwashes on resin composites with rough surfaces can cause discoloration which compromises the esthetic of patients. The present study aimed to evaluate the in vitro color stability of Forma (Ultradent Products, Inc., South Jordan), Tetric N-Ceram (Ivoclar Vivadent, Schaan, [...] Read more.

The use of chlorhexidine-based mouthwashes on resin composites with rough surfaces can cause discoloration which compromises the esthetic of patients. The present study aimed to evaluate the in vitro color stability of Forma (Ultradent Products, Inc., South Jordan), Tetric N-Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Z350XT (3M, ESPE, St. Paul, MN, USA) resin composites, with and without polishing, after being immersed in a 0.12% chlorhexidine (CHX)-based mouthwash at different times. The present in vitro experimental and longitudinal study used 96 nanohybrid resin composite blocks (Forma, Tetric N-Ceram and Filtek Z350XT) 8 mm in diameter and 2 mm thick, evenly distributed. Each resin composite group was divided into two subgroups (n = 16) with and without polishing and then immersed in a 0.12% CHX-based mouthwash for 7, 14, 21 and 28 days. Color measurements were performed with a calibrated digital spectrophotometer. Nonparametric tests were used to compare independent (Mann–Whitney U and Kruskal–Wallis) and related (Friedman) measures. In addition, the Bonferroni post hoc correction was used considering a significance level of p < 0.05. All polished and unpolished resin composites presented color variation < 3.3 when immersed for up to 14 days in 0.12% CHX-based mouthwash. The polished resin composite with the lowest color variation (ΔE) values over time was Forma, and the one with the highest values was Tetric N-Ceram. When comparing the color variation (ΔE) over time, it was observed that the three resin composites, with and without polishing, presented a significant change (p < 0.001), although these changes in color variation (ΔE) were evident from 14 days between each color acquisition (p < 0.05). The unpolished Forma and Filtek Z350XT resin composites showed significantly more color variation than the same polished ones at all times when immersed in a 0.12% CHX-based mouthwash for 30 s daily. In addition, every 14 days, all three resin composites with and without polishing showed a significant color change, while, every 7 days, color stability was maintained. All the resin composites showed clinically acceptable color stability when exposed for up to 14 days to the above-mentioned mouthwash. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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18 pages, 907 KiB

Open AccessArticle

Shear Bond Strength of Resin Luting Materials to Lithium Disilicate Ceramic: Correlation between Flexural Strength and Modulus of Elasticity

by Masao Irie, Masahiro Okada, Yukinori Maruo, Goro Nishigawa and Takuya Matsumoto

Polymers 2023, 15(5), 1128; https://doi.org/10.3390/polym15051128 - 23 Feb 2023

Cited by 4 | Viewed by 3244

Abstract

This study investigates the effect of the curing mode (dual-cure vs. self-cure) of resin cements (four self-adhesive and seven conventional cements) on their flexural strength and flexural modulus of elasticity, alongside their shear bond strength to lithium disilicate ceramics (LDS). The study aims [...] Read more.

This study investigates the effect of the curing mode (dual-cure vs. self-cure) of resin cements (four self-adhesive and seven conventional cements) on their flexural strength and flexural modulus of elasticity, alongside their shear bond strength to lithium disilicate ceramics (LDS). The study aims to determine the relationship between the bond strength and LDS, and the flexural strength and flexural modulus of elasticity of resin cements. Twelve conventional or adhesive and self-adhesive resin cements were tested. The manufacturer’s recommended pretreating agents were used where indicated. The shear bond strengths to LDS and the flexural strength and flexural modulus of elasticity of the cement were measured immediately after setting, after one day of storage in distilled water at 37 °C, and after 20,000 thermocycles (TC 20k). The relationship between the bond strength to LDS, flexural strength, and flexural modulus of elasticity of resin cements was investigated using a multiple linear regression analysis. For all resin cements, the shear bond strength, flexural strength, and flexural modulus of elasticity were lowest immediately after setting. A clear and significant difference between dual-curing and self-curing modes was observed in all resin cements immediately after setting, except for ResiCem EX. Regardless of the difference of the core-mode condition of all resin cements, flexural strengths were correlated with the LDS surface upon shear bond strengths (R² = 0.24, n = 69, p < 0.001) and the flexural modulus of elasticity was correlated with them (R² = 0.14, n = 69, p < 0.001). Multiple linear regression analyses revealed that the shear bond strength was 17.877 + 0.166, the flexural strength was 0.643, and the flexural modulus was (R² = 0.51, n = 69, p < 0.001). The flexural strength or flexural modulus of elasticity may be used to predict the bond strength of resin cements to LDS. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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17 pages, 6243 KiB

Open AccessArticle

Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites

by Baoming Wang, Shengzong Ci, Mingzhe Zhou, Chengrui Di, Junwei Yu, Bo Zhu and Kun Qiao

Polymers 2023, 15(3), 725; https://doi.org/10.3390/polym15030725 - 31 Jan 2023

Cited by 18 | Viewed by 2573

Abstract

Epoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins [...] Read more.

Epoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins and their carbon fibre composites was carried out via artificially accelerated experiments under hygrothermal and salt mist conditions. The moisture penetration along the depth, water absorption, appearance, hardness, density of the epoxy resins, and variation patterns of the impact strength and tensile strength of the epoxy-based composites were investigated. The ageing mechanisms were explored using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both ageing modes had essentially similar influences on the properties of the resins and their composites; moreover, they did not significantly affect the chemical structure and microstructure of the epoxy resin, with the physical adsorption of water primarily observed during the ageing process. The moisture absorption behaviour of the epoxy obeyed Fick’s law. Although the water penetration rate in the salt mist ageing mode was slightly higher than that in the hygrothermal ageing mode during the early ageing stage, it was essentially the same during the later stage. The final moisture absorption rate at saturation was approximately 1.1% under both modes. The flexural strengths and impact strengths of the composites in both ageing modes followed a similar trend. They decreased gradually with the ageing time and then stabilized at almost the same value. The flexural strength was reduced from 803 MPa to 760 MPa and the impact strength from 383 J/m² to 310 J/m², indicating a decrease of approximately 5.4% and 19%, respectively. The absorbed water during the ageing process caused micro-cracks at the interface between the fibres and resin, weakening the interfacial strength and reducing the mechanical properties of the composites. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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13 pages, 3921 KiB

Open AccessArticle

Microstructure and Shear Behaviour of Sn-3.0Ag-0.5Cu Composite Solder Pastes Enhanced by Epoxy Resin

by Peng Zhang, Songbai Xue, Lu Liu, Jie Wu, Qingcheng Luo and Jianhao Wang

Polymers 2022, 14(23), 5303; https://doi.org/10.3390/polym14235303 - 4 Dec 2022

Cited by 8 | Viewed by 2417

Abstract

With the rapid development of microelectronics packaging technology, the demand for high-performance packaging materials has further increased. This paper developed novel epoxy-containing Sn-3.0Ag-0.5Cu (SAC305-ER) composite solder pastes, and the effects of epoxy resin on their spreading performance, microstructure, and shear behaviour were analysed. [...] Read more.

With the rapid development of microelectronics packaging technology, the demand for high-performance packaging materials has further increased. This paper developed novel epoxy-containing Sn-3.0Ag-0.5Cu (SAC305-ER) composite solder pastes, and the effects of epoxy resin on their spreading performance, microstructure, and shear behaviour were analysed. The research results showed that with the addition of epoxy resin, SAC305 solder pastes exhibited exceptional spreadability on Cu substrates, which could be attributed to the reduction in the viscosity and the surface tension of the composite solder pastes. With the addition of epoxy resin, the solder matrix microstructure and interfacial morphology of SAC305-ER composite solder joints remained unchanged. However, continuous resin protective layers were observed on the surface of SAC305-ER composite solder joints after the reflow process. The shear properties of the composite solder joints were enhanced by the extra mechanical bonding effect provided by resin layers. When the epoxy resin content was 8 wt%, the shear forces of SAC305-ER composite solder joints reached the maximum value. Fracture analysis indicated that cracked epoxy resin was observed on the surface of SAC305-ER composite solder joints, indicating that the epoxy resin also underwent obvious deformation in the shear test. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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11 pages, 3010 KiB

Open AccessArticle

Improving the Thermal Stability and Flame Retardancy of Epoxy Resins by Lamellar Cobalt Potassium Pyrophosphate

by Qinghong Kong, Lan Li, Manman Zhang, Huiyu Chai, Weixi Li, Fang Zhu and Junhao Zhang

Polymers 2022, 14(22), 4927; https://doi.org/10.3390/polym14224927 - 15 Nov 2022

Cited by 9 | Viewed by 2372

Abstract

In order to improve the fire retardancy of epoxy resin (EP), lamellar cobalt potassium pyrophosphate (LCPP) nanocrystal whiskers with a length of 100–300 nm were designed and synthesized by a liquid technique. LCPP with high thermal stability was blended into EP to prepare [...] Read more.

In order to improve the fire retardancy of epoxy resin (EP), lamellar cobalt potassium pyrophosphate (LCPP) nanocrystal whiskers with a length of 100–300 nm were designed and synthesized by a liquid technique. LCPP with high thermal stability was blended into EP to prepare the EP/LCPP composites. The results show that the EP/LCPP composites have higher thermal stability and produce more residues compared to pure EP. The combustion results display that the LOI value of the EP/10wt%LCPP composites was significantly improved to 35.9%, and the EP/6wt%LCPP composite can reach a UL-94 V-1 rating. Additionally, the peak heat release rate and peak smoke production rate of the EP/10wt%LCPP composites dramatically decreased by 43.8% and 48.5%, respectively. The improved flame retardancy and smoke suppression are mainly attributed to the inherent physical barrier of LCPP and the excellent catalytic carbonization ability of LCPP. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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13 pages, 8939 KiB

Open AccessArticle

Synthesis, Curing Behaviors and Properties of a Bio-Based Trifunctional Epoxy Silicone Modified Epoxy Thermosets

by Dan Qian, Jiahai Zhou, Jieyuan Zheng, Jun Cao, Jintao Wan and Hong Fan

Polymers 2022, 14(20), 4391; https://doi.org/10.3390/polym14204391 - 18 Oct 2022

Cited by 9 | Viewed by 3294

Abstract

Tremendous effort has been focused on improving the toughness of epoxy, but the common approaches diminish the mechanical properties. In this work, a new silicone-modified trifunctional epoxy monomer SITEUP is synthesized from the hydrosilylation transformation of eugenol epoxy (EPEU) and tris-(dimethylsiloxy)phenylsilane. The chemical [...] Read more.

Tremendous effort has been focused on improving the toughness of epoxy, but the common approaches diminish the mechanical properties. In this work, a new silicone-modified trifunctional epoxy monomer SITEUP is synthesized from the hydrosilylation transformation of eugenol epoxy (EPEU) and tris-(dimethylsiloxy)phenylsilane. The chemical structures and curing kinetics of SITEUP are investigated based on ¹H-NMR, ¹³C-NMR, MADLI-TOF-MS, and DSC analyses. SITEUP is introduced into DGEBA/IPDA systems as a functional modifier in varied loadings for toughening the resulting epoxy thermosets. The impact strength of the modified epoxy thermosets containing 20% SITEUP is 84% higher than that of the pristine epoxy thermoset and also maintains high flexural strength. Further morphology study reveals that the plastic deformation caused by siloxane segments is the key factor accounting for the enhanced toughness of the finalized epoxy thermosets. Si-O-Si segments incorporated into the thermosetting network could absorb more energy by increasing the mobility of polymer chains under external stress and led to improved thermal stability and damping characteristics. In addition, SITEUP is able to decrease the surface tension and increase the hydrophobic properties of the resultant epoxy materials. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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16 pages, 6164 KiB

Open AccessArticle

The Influence of Polycaprolactone on Structural Changes of Dusts from Molding Sands with Resin-Based Binder before and after the Biodegradation Process

by Katarzyna Major-Gabryś, Iwona Stachurek, Małgorzata Hosadyna-Kondracka and Marta Homa

Polymers 2022, 14(13), 2605; https://doi.org/10.3390/polym14132605 - 27 Jun 2022

Cited by 1 | Viewed by 1626

Abstract

Resin-based binders are one of the main materials used in foundry molding and core sands. This work adds to the research on self-curing sands with furfuryl resin, which dominates in the production of large-size castings. The work concerns the possibility of using biodegradable [...] Read more.

Resin-based binders are one of the main materials used in foundry molding and core sands. This work adds to the research on self-curing sands with furfuryl resin, which dominates in the production of large-size castings. The work concerns the possibility of using biodegradable polymers as a component of resin-based binders. Biodegradable or partially biodegradable polymers are a group of materials which have an increasing level of importance in many areas of life and technology. This is mainly due to the increase in waste deposited in landfills, water and soil. This problem also concerns waste from the casting production process with the use of disposable molds with resin-based binders, which are mainly residues from their mechanical regeneration process. The aim of the research presented in this paper was to determine the effect of polycaprolactone (PCL) on the structure of post-regeneration dust from molding sands before and after the biodegradation process carried out in a water environment. Structure studies were carried out by Fourier transform infrared spectroscopy (FTIR) and the changes in the mass by TG/DTA-QMS analysis. The article also presents the results of the research of the morphology carried out by scanning electron microscopy (SEM) and the chemical oxygen demand index (COD) in water extracts of dust samples. Full article

(This article belongs to the Special Issue Resin-Based Polymer Materials and Related Applications)

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