Research And Preparation Of Polypropylene Glycol In ABS Granulation

The preparation and purification process of polypropylene glycol was studied. The high molecular weight(Mn=2000～2100)polypropylene glycol glycerin ether was sythesized from propylene oxide and glycerin with potassium hydroxide as catalyst. The effects of some reaction parameters,such as purity of raw material , the ratio of feedstocks, catalyst mass fraction, reaction temperature , solvent and stirring velocity on the quality of products were investigated in detail. The crude PPG was purified with neutralization-absorption process and the experimental conditions of crystallization, decolor , dehydration and removement of metal irons were investigated respectively. The influence of absorbent on the product purification was also investigated .Results show that the optimal conditions in the synthesis process of PPG are follows: po/pp=34—39(mol/mol), reaction temperature: 105±2℃, catalyst mass fraction: 0.5—0.7%( PPG weight), stirring velocity: 450rpm .The resulted products of PPG were comparable to those from foreign countries and it can be used as lubricant in ABS granulation . Neutralization-absorption process is suitable for rectification of polypropylene glycol glycerin ether and the optimal conditions in the process can be described as follows:phosphous acid: 2.16—2.24%( PPG weight), crystral seed: 0.2—0.3%,agent for the crystal particle increasing(T—501)0.4%,absorbent: 0.6%. The antioxidative stability of PPG can be effectively improved by adding antioxidant to the product.