响应面法优化废旧PET催化醇解工艺

Optimization of Waste Polyethylene Terephthalate Catalyzed Alcoholysis Process by Response Surface Methodology

摘要:

在常压下采用催化剂一步醇解废旧聚酯(PET)工艺制备聚酯多元醇，并采用物理发泡方式用该聚酯多元醇制备了硬质聚氨酯泡沫塑料，达到废旧PET的循环利用。以催化醇解得到聚酯多元醇的羟值、酸值和黏度为指标，筛选催化剂用量、醇解剂用量和醇解时间为主要因素，通过响应面法优化得到催化醇解废旧PET的最佳工艺条件，即质量分数0.3%（占PET的质量，下同）的Sb2O3作为解聚的催化剂、质量分数100%的二甘醇为醇解剂，醇解反应时间为2.5h，通过实验验证表明该条件可靠，实际得到的聚酯多元醇羟值503.9mgKOH/g，酸值2.4mgKOH/g，室温粘度1310mPa·s，以该聚酯多元醇为原料制备硬质聚氨酯泡沫的导热系数为0.02～0.03W/(m·K)，密度为40～50kg/m3，表明通过该方法实现废旧PET的循环利用是可行的，并提高了其循环利用价值。

Abstract:

The polyester polyol was prepared by depolymerizing polyethylene terephthalate(PET) using catalyst with single step depolymerization technology in ordinary pressure,rigid polyurethane foam was prepared by using the polyester polyol with physical foaming method,to achieve the purpose of recycling of used PET.The hydroxyl,acid and viscosity of the polyester polyol as the response value.Dosages of catalyst and alkali，pyrolysis time were chosen as principal factors,and the optimized conditions for alcoholysis of PET were obtained with using response surface methodology(RSM) were as follows:catalyst Sb2O3 0.3% of PET weight,alcoholysis agents diglycol(DEG) 100% of PET weight,reaction time 2.5 hours.The experimental verification indicated that the conditions by RSM analysis were reliable,the hydroxyl value,acid value and viscosity of the product were 503.9 mgKOH/g,2.4 mgKOH/g and 1310 mPa·s,respectively.Rigid polyurethane foam is made with the polyester polyol,its coefficient of thermal conductivity is 0.02～0.03 W/(m·K) and density is 40～50 kg/m3,it shows that the recycling of used PET can be achieved through this method,and its recycling value was improved.