Abstract

Incorporating carboxyl group into the poly(vinyl chloride) (PVC) resin can endow PVC with reactivity in some applications. In this work, poly(vinyl chloride)-co-poly(acrylic acid) random copolymer (PVCA) with low average number molecular weight (M_n, ∼10 k) is synthesized by precipitation polymerization. By tuning acrylic acid dropping rate, the PVCA copolymer with much more uniform copolymer composition is obtained in comparison to all monomer-in process. Subsequently, the PVCA is utilized as a novel polymer modifier for the surface treatment of CaCO₃ particles and its effect on the mechanical properties of obtained rigid PVC composites are evaluated systematically. As a result, the PVAC modified CaCO₃ particles exhibit uniform dispersibility and excellent compatibility in PVC matrix. Additionally, the thermal stability is improved significantly owing to the calcium ions on the surface of CaCO₃ particles, which scavenge the hydrogen chloride and retard the autocatalytic dehydrochlorination process. Impressively, it also has an enhancement both in tensile strength (ca. 46.4 MPa, and 119.8% elongation at break) and in impact strength (2.7 kJ m⁻²) in comparison to those modified by commercialized agents such as stearic acid and titanate ester. This work provides valuable insights for the preparation of vinyl chloride copolymers and opens a new application.

摘要

在聚氯乙烯 (PVC) 树脂中加入羧基可使 PVC 在某些应用中具有反应性。在这项工作中，聚（氯乙烯）-共聚（丙烯酸）无规共聚物（PVCA）具有低平均数分子量（M _n，~10 k）通过沉淀聚合合成。通过调整丙烯酸滴速，与所有单体工艺相比，PVCA 共聚物具有更均匀的共聚物组成。随后，PVCA 作为一种新型聚合物改性剂用于 CaCO ₃颗粒的表面处理，并系统地评估了其对所得硬质 PVC 复合材料机械性能的影响。因此，PVAC 改性 CaCO ₃颗粒在PVC基体中表现出均匀的分散性和优异的相容性。此外，由于CaCO ₃颗粒表面的钙离子清除氯化氢并阻碍自催化脱氯化氢过程，热稳定性显着提高。令人印象深刻的是，与使用硬脂酸和钛酸酯等商业化试剂改性的那些相比，它还在拉伸强度（约 46.4 MPa，断裂伸长率为 119.8%）和冲击强度（2.7 kJ m ^-2）方面都有所提高. 这项工作为氯乙烯共聚物的制备提供了宝贵的见解，并开辟了新的应用领域。