Dual Actions of a Commercial Sorbitol Derivative on Crystallization Behavior of Poly(1,4-butylene adipate)

• Published in: ACS omega 2019-04, Vol.4 (4), p.7005-7013
• Main Authors: Zhang, Kai, Wang, Cai-Shui, Zhou, Qian, Ye, Hai-Mu
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.9b00161

Biodegradable poly­(1,4-butylene adipate) (PBA) has been highlighted of distinct polymorphism and receives extensive research by adding nucleating agents. Usually, only a single nucleating mechanism is proposed for each composite system, which should not be sufficient. In present work, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)­methylene]-nonitol sorbitol (NX), a commercial sorbitol derivative, was incorporated into the PBA matrix to regulate the crystallization behavior. It is found that the non-isothermal crystallization temperature rises first and then declines, but the α-form crystal-forming ability becomes stronger with the increasing NX content, which is due to the limited solubility of NX in PBA. When NX is totally dissolved, the specific butterfly molecular shape of NX helps PBA chains form the gauche conformation, simultaneously promoting the crystallization rate and α crystal formation. However, once the NX content is ≥1%, crystallites of NX appear and play as physical cross-linking points for PBA chains; then, the mobility restriction becomes the major mechanism, which would slow down the crystallization rate but significantly enhance the formation of the α-form crystal-forming ability. PBA/NX composites possess a considerably lower degradation rate than neat PBA. Thus, this work demonstrates a novel additive of the dual mechanism to regulate the crystallization behavior and further the degradation rate of PBA.