Unsaturated Polyesters from PET Waste: Kinetics of Polycondensation
Unsaturated Polyesters from PET Waste: Kinetics of Polycondensation
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来自 PET 废料的不饱和聚酯：缩聚动力学
DOI：
10.1002/app.1987.070340120
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发表时间：
1987
影响因子：
3
通讯作者：
V. M. Nadkarni
中科院分区：
文献类型：
--
作者：
U. Vaidya;V. M. Nadkarni
以不同质量比的丙二醇为催化剂，对PET废料进行糖酵解。分析糖酵解产物的羟值、数均分子量和游离二醇的量。将糖酵解产物与马来酸酐以1.1的羟基与羧基比反应。对照树脂是通过使邻苯二甲酸酐、马来酸酐和丙二醇反应制备的通用不饱和聚酯。聚酯化的加热方案与工业方法中通常使用的加热方案相当，在180和200°C下具有3-4小时的两个等温平台。分别在180和200°C下测定反应速率和速率常数。PET基不饱和聚酯的动力学与通用树脂的动力学进行了比较。结果表明，聚对苯二甲酸乙二酯废料可被丙二醇解聚至分子量为276-480的范围。酯化反应符合三级动力学。PET基体系的聚酯化速率高于通用树脂。PET基体系的渗透率高于通用树脂。基于PET的体系花费约10小时达到32 mg KOH/g的酸值，而通用树脂花费约25小时达到相同的酸值。
PET waste was glycolyzed by propylene glycol at different weight ratios. The glycolyzed products were analyzed for hydroxyl value, number average molecular weight, and the amount of free glycol. The glycolyzed products were reacted with maleic anhydride at a hydroxyl to carboxyl ratio of 1.1. The control resin was a general purpose unsaturated polyester prepared by reacting phthalic anhydride, maleic anhydride, and propylene glycol. The heating schedule of the polyesterification was comparable to that normally employed in the industrial process, with two isothermal plateau of 3–4 h at 180 and 200°C. The rate of reactions and rate constants were determined separately at 180 and 200°C. The kinetics of the PET-based unsaturated polyesters was compared with that of the general purpose resin. It was found that the PET waste could be depolymerized by propylene glycol to a molecular weight range of 276–480. The polyesterification reactions followed a third-order kinetics. The rates of polyesterification of PET based systems were higher than that of the general purpose resin. PET-based systems were higher than that of the general purpose resin. PET-based systems took about 10 h to reach an acid value of 32 mg KOH/g whereas the general purpose resin took about 25 h to reach the same acid value.