The Synthesis Of Poly(Trimethylene Terephthalate) And Process Enlarging Of Direct Polycondensation Of Poly(Lactide Acid)

The author found that the ternary composite catalytic systems are also suit for direct melt condensation polymerization of poly (lactic acid) (PLA). The reaction condition was optimized in the process of scaring up of precondensation stage and the best vacuum is 500 Pa, the reaction time is 12 h. In this dissertation, we design and manufact 5 L polymerization reactor according to the process conditions. The effect of reaction heat transfer and mass transfer that caused by scaring up have been solved. The system has also been modificated and optimized in order to achieving high weight PLA products, whose molecular weight are 20 w, PDI are 4.4.We also study the the influence of lactide to PDI in the process of production, and test the different processing methods to deal with lactide. With adding of assistant catalyst Sn(Oct)2, the PDI of product will narrow greatly, and the optimal inventory is 0.1 wt% of raw material. In this dissertation, we test the material properties of PLA which are obtained on the 5 L reactor, and try to optimize the product material properties. The melting temperature(Tm) of PLA product is 140.2℃, the degradation temperature is 316.1℃and the physical or processing performance has reached the standard of commercial PLA which called Nature Works 2002D.We constructs the titanium(IV) isopropoxide (Ti[OCH(CH3)2]4) /p-toluenesulfonic acid(TSA)/2,2-dimethylol propionic acid(DMPA) ternary compound catalytic system, and achieve the goal of high molecular weight polytrimethylene terephthalate(PTT). The best feeding of Ti[OCH (CH3)2]4 in the ternary compound catalytic system is 0.085 wt% of TPA quality ratio, and the best feeding of TSA or DMPA is respectively 0.16 wt% and 0.11 wt%. The optimal TPA and 1,3-PDO ingredient ratio is 1:1.4, the optimal time in polycondensation is 1 h, and finally get fiber grade PTT.