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21 pages, 2377 KB

Open AccessArticle

Closed-Loop Recycling of Poly(vinyl butyral) Interlayer Film via Restabilization Technology

by Vasilis Nikitakos, Athanasios D. Porfyris, Konstantinos Beltsios, Rudolf Pfaendner, Beatriz Yecora, Angelica Perez, Filip Brkić, Filip Miketa and Constantine D. Papaspyrides

Polymers 2025, 17(3), 317; https://doi.org/10.3390/polym17030317 - 24 Jan 2025

Cited by 4 | Viewed by 2862

Abstract

Polyvinyl butyral (PVB) is a specialty polymer primarily used as an interlayer in laminated glass applications with no current circularity plan after the end of its life. This study presents a comprehensive recycling strategy for postconsumed PVB wastes based on a remelting–restabilization approach. Thermo-oxidative degradation of PVB was analyzed under heat and shear stress conditions in an internal mixer apparatus. The degradation mechanism of plasticized PVB (p-PVB) and unplasticized PVB (u-PVB) was identified as chain scission through melt flow rate (MFR), intrinsic viscosity (IV), and yellowness index (YI) characterization. Six different antioxidant (AO) formulations were screened for their effectiveness in inhibiting degradation in both neat u-PVB and p-PVB, as well as retrieved PVB. The phenolic antioxidants 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol were found to be the most effective ones based on MFR, oxidation onset temperature (OOT), and YI evaluations, while the optimal AO concentration was determined at 0.3% w/w. Furthermore, upscaling of the process was achieved by mixing virgin PVB and high-quality retrieved PVB wastes with AOs in a twin-screw extruder. Testing of the recycled samples confirmed that the selected AOs offered resilience against degradation at reprocessing and protection during the next service life of the material. Full article

(This article belongs to the Section Polymer Chemistry)

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20 pages, 10642 KB

Open AccessArticle

A UV-Protective Textile Coating Based on Recycled Poly(vinyl butyral) (PVB): A New Life for a Waste Polymer

by Noemi Cei, Ilaria Canesi, Stefano Nejrotti, Giorgia Montalbano, Hamideh Darjazi, Alessandro Piovano, Matteo Bonomo, Alberto Fina, Beatriz Yecora, Angelica Perez, Claudia Barolo, Claudio Gerbaldi and Daniele Spinelli

Polymers 2024, 16(23), 3439; https://doi.org/10.3390/polym16233439 - 7 Dec 2024

Cited by 9 | Viewed by 3165

Abstract

Polyvinyl butyral (PVB) is a high-performance thermoplastic polymer, commonly used as an interlayer material in laminated safety glass for the automotive and architectural sectors. Currently, there is no end-of-life cycle program for a substantial amount of PVB film, which mainly ends up in landfills. According to a circular approach, PVB can be revalorized after efficient separation and recovery from glass. Thus, the aim of this work was to develop functional coatings for textile applications using recycled PVB (re-PVB), also in combination with an organic UV absorber, to enable the production of UV-protective final coated fabrics. The re-PVB-coated fabrics were obtained through an industrially scalable spraying process (leading to an average weight increase of 20 ± 3 wt.%), and the effectiveness of the application was evaluated according to different characterization techniques, such as FT-IR (Fourier transform–infrared) spectroscopy, SEM (scanning electron microscope), a washing test, a mechanical test, a thermo-physiological test, and the ultraviolet protection factor (UPF). Based on the results, the re-PVB-coated fabrics appeared stable upon washing (with a negligible weight loss compared to the average amount of coating) and effective in UV protection (with a final UPF being four times higher and a reduced UVA transmittance from 2.0% to 0.6%). Full article

(This article belongs to the Collection Progress in Polymer Applications)

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21 pages, 9039 KB

Open AccessArticle

An Integrated Characterization Strategy on Board for Recycling of poly(vinyl butyral) (PVB) from Laminated Glass Wastes

by Vasilis Nikitakos, Athanasios D. Porfyris, Konstantinos Beltsios, Constantine Papaspyrides, Simone Bordignon, Michele R. Chierotti, Stefano Nejrotti, Matteo Bonomo, Claudia Barolo, Alessandro Piovano, Rudolf Pfaendner, Beatriz Yecora and Angelica Perez

Polymers 2024, 16(1), 10; https://doi.org/10.3390/polym16010010 - 19 Dec 2023

Cited by 14 | Viewed by 4732

Abstract

Polyvinyl butyral (PVB) is widely used as an interlayer material in laminated glass applications, mainly in the automotive industry, but also for construction and photovoltaic applications. Post-consumed laminated glass is a waste that is mainly landfilled; nevertheless, it can be revalorized upon efficient separation and removal of adhered glass. PVB interlayers in laminated glass are always plasticized with a significant fraction in the 20–40% w/w range of plasticizer, and they are protected from the environment by two sheets of glass. In this work, the aim is to develop a thorough characterization strategy for PVB films. Neat reference PVB grades intended for interlayer use are compared with properly processed (delaminated) post-consumed PVB grades from the automotive and construction sectors. Methods are developed to open opportunities for recycling and reuse of the latter. The plasticizer content and chemical nature are determined by applying well-known analytical techniques, namely, FT-IR, TGA, NMR. The issue of potential aging during the life cycle of the original laminated material is also addressed through NMR. Based on the findings, a sensor capable of directly sorting PVB post-consumer materials will be developed and calibrated at a later stage. Full article

(This article belongs to the Section Polymer Chemistry)

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22 pages, 7035 KB

Open AccessArticle

Electrospun Sound-Absorbing Nanofibrous Webs from Recycled Poly(vinyl butyral)

by Petr Filip, Tomas Sedlacek, Petra Peer and Martin Juricka

Polymers 2022, 14(22), 5049; https://doi.org/10.3390/polym14225049 - 21 Nov 2022

Cited by 8 | Viewed by 2905

Abstract

The amount of poly(vinyl butyral) (PVB) foils added to car windscreens to suppress glass shattering represents a huge worldwide volume of the material, and once a vehicle is end-of-life it also becomes a significance contributor to landfill. The recycling of PVB materials from windscreens has been expensive and despite improvements in recycling technologies, the landfill burden still increases. However, an increase in oil prices can shift the economic balance and stimulates the possible applicability of recycled PVB. As PVB is a relatively easy electrospinnable material, it is shown that nanofibrous mats produced from recycled PVB blends in ethanol exhibit very good sound-absorbing properties. To achieve an optimal composition between virgin and recycled PVB blends, a series of their ratios was consecutively characterized using various techniques (rheometry, SEM, FTIR, DSC, TGA, DMA, an impedance tube for determining sound absorbance). The best result was obtained with two wt. portions of 8 wt.% solution of virgin PVB in ethanol and one wt. portion of 12 wt.% solution of recycled PVB in ethanol. Full article

(This article belongs to the Special Issue Electrospinning Technology to Produce Innovative Nanostructured Polymer Materials: Current Applications and Future Perspectives)

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