*Article* **Role of Organically-Modified Zn-Ti Layered Double Hydroxides in Poly(Butylene Succinate-Co-Adipate) Composites: Enhanced Material Properties and Photodegradation Protection**

**Jie-Mao Wang, Hao Wang, Erh-Chiang Chen, Yun-Ju Chen and Tzong-Ming Wu \***

Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan; D9866023@mail.nchu.edu.tw (J.-M.W.); eddie115923@icloud.com (H.W.); erchiang.chen@gmail.com (E.-C.C.); bitcoin2243@gmail.com (Y.-J.C.)

**\*** Correspondence: tmwu@dragon.nchu.edu.tw

**Abstract:** In this research, the effects of Zn-Ti layered double hydroxide (Zn-Ti LDH) as a UVprotection additive, which was added to the poly(butylene succinate-co-adipate) (PBSA) matrix, were investigated. Stearic acid was used to increase the hydrophobicity of Zn-Ti LDH via ion-exchange method. Transmission electron microscopy images of PBSA composites showed that modified Zn-Ti LDH (m-LDH) well-dispersed in the polymer matrix. Due to the effect of heterogeneous nucleation, the crystallization temperature of the composite increased to 52.9 ◦C, and the accompanying crystallinity increased to 31.0% with the addition of 1 wt% m-LDH. The additional m-LDH into PBSA copolymer matrix significantly enhanced the storage modulus, as compared to pure PBSA. Gel permeation chromatography and Fourier transform infrared spectroscopy analysis confirmed that the addition of m-LDH can reduce the photodegradation of PBSA.

**Keywords:** photodegradation; biodegradable polymer; poly(butylene succinate-co-adipate); Zn-Ti LDH
