Liu Qing, Chen Ning, Bai Shibing, Li Wenzhi
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University Chengdu 610065 China
State Key Laboratory of Special Functional Water Proof Materials, Beijing Oriental Yuhong Waterproof Technology Co., Ltd Beijing 100000 China.
RSC Adv. 2018 Jan 12;8(5):2804-2810. doi: 10.1039/c7ra12941f. eCollection 2018 Jan 9.
The thermal processing of poly(vinyl alcohol) (PVA) is a big challenge worldwide. In this article, silver nitrate (AgNO), which can combine with the hydroxyl groups of PVA and water, was introduced to further improve the thermal processability of the poly(vinyl alcohol)/water system. The water states, thermal performance, and rheological properties of PVA modified by AgNO were investigated. The results showed that with the increasing of AgNO content, the content of bound water in system increased ascribing to the interaction among PVA, water and AgNO, indicating that the bondage of PVA matrix on water enhanced, thus retarding the tempestuous evaporation of water in system during melt process and making more water remain in system to play the role of plasticizer. Meanwhile, that AgNO combined with the hydroxyl groups of PVA further weakened the self-hydrogen bonding of PVA, guaranteeing a lower melting point and higher decomposition temperature, and broadening the thermal processing window. The rheological properties of the modified PVA system showed that the torque and die pressure of the modified PVA system turned to stabilization during melt processing, testifying that the thermal processability of the PVA/water system was largely improved.
聚乙烯醇（PVA）的热加工在全球范围内都是一项巨大的挑战。在本文中，引入了能与PVA的羟基和水结合的硝酸银（AgNO₃），以进一步改善聚乙烯醇/水体系的热加工性能。研究了经AgNO₃改性的PVA的水状态、热性能和流变性能。结果表明，随着AgNO₃含量的增加，体系中结合水的含量增加，这归因于PVA、水和AgNO₃之间的相互作用，表明PVA基体对水的束缚增强，从而在熔融过程中抑制了体系中水的剧烈蒸发，使更多的水保留在体系中起到增塑剂的作用。同时，AgNO₃与PVA的羟基结合进一步削弱了PVA的自氢键，保证了较低的熔点和较高的分解温度，并拓宽了热加工窗口。改性PVA体系的流变性能表明，改性PVA体系在熔融加工过程中的扭矩和模头压力趋于稳定，证明PVA/水体系的热加工性能有了很大提高。
