Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14965/115, Tehran, Iran.
Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14965/115, Tehran, Iran.
Dent Mater. 2020 Jun;36(6):e169-e183. doi: 10.1016/j.dental.2020.03.006. Epub 2020 Apr 16.
The aim of this study was to synthesize poly(acrylic acid-co-itaconic acid) (PAA-co-PIA) ionomer through a novel precipitation photopolymerization technique. The ionomer was characterized and the effect of its structural parameters, such as molecular weight and copolymer composition were investigated on the mechanical properties of glass-ionomer prepared using the ionomer.
Design of experiment (DOE) was used to examine the effect of monomer ratio and the amount of chain transfer agent on the molecular weight and final conversion of the ionomers synthesized through the precipitation photopolymerization. The copolymer compositions were identified using FTIR and H-NMR spectroscopy. The molecular weights of the copolymers were evaluated by GPC. A series of PAA-co-PIA copolymers were then synthesized via the photopolymerization technique in three monomer ratios and two molecular weight ranges (high and low) to study the properties of the glass ionomers thereof. Experimental dental glass-ionomer cements were prepared by mixing the synthesized polymers with glass powder and their compressive properties were determined according to ISO 9917-1:2007 after storing for 0, 1, 7 and 28 days in distilled water. The scanning electron microscopy (SEM) was used to study the fracture surface morphology of the cements.
The PAA-co-PIA polymers were synthesized by the photopolymerization method in a short time and high purity. The DOE showed that by decreasing the acrylic acid/itaconic acid ratio and increasing the amount of transfer agent, the molecular weight and final conversion decreased significantly. By increasing the itaconic acid content in the copolymer composition and increasing the molecular weight in a constant copolymer composition, the compressive strength and modulus were increased. Microstructures revealed that cements made of the higher molecular weight poly acids showed lower cracks and voids.
The precipitation photopolymerization technique provides a promising and facile method in the synthesis of ionomers which are used in dental cements and other application.
本研究旨在通过一种新颖的沉淀光聚合技术合成聚丙烯酸-co-衣康酸共聚物（PAA-co-PIA）离聚物。对该离聚物进行了表征，并研究了其结构参数（如分子量和共聚组成）对使用该离聚物制备的玻璃离子体的力学性能的影响。
采用实验设计（DOE）考察了单体比对沉淀光聚合过程中合成的离聚物分子量和最终转化率的影响，以及链转移剂用量的影响。采用傅里叶变换红外光谱（FTIR）和核磁共振氢谱（H-NMR）对共聚物组成进行了鉴定。采用凝胶渗透色谱（GPC）对共聚物的分子量进行了评估。然后通过光聚合技术，在三种单体比和两种分子量范围（高和低）下合成了一系列 PAA-co-PIA 共聚物，以研究其玻璃离子体的性能。将合成的聚合物与玻璃粉混合，制备实验牙科玻璃离子水门汀，根据 ISO 9917-1:2007 标准，在蒸馏水中储存 0、1、7 和 28 天后，测定其压缩性能。采用扫描电子显微镜（SEM）研究了水门汀的断裂面形貌。
通过光聚合方法在短时间内以高纯度合成了 PAA-co-PIA 聚合物。DOE 表明，通过降低丙烯酸/衣康酸比并增加转移剂用量，分子量和最终转化率显著降低。在恒定共聚组成下，增加共聚物组成中的衣康酸含量并增加分子量，压缩强度和模量增加。微观结构表明，由较高分子量聚酸制成的水门汀显示出较低的裂缝和空隙。
沉淀光聚合技术为牙科水门汀和其他应用中使用的离聚物的合成提供了一种有前途且简便的方法。
