Lipase Catalyzed Synthesis Of Poly Caprolactone And The Degradation Of Products

As an important biodegradable polymer material,Poly (ε-Caprolactone) (PCL) has been widely used in the field of biological, chemical, medical material etc. It cause the heavy metal residues by the traditional chemical methods of to synthetic and show toxicity,which limit the use of PCL. This article explored the system of PCL synthesis ca-catalyzed by enzymes from the perspective of bio-catalysis,and explored the degradation performance of PCL which catalytic by the enzyme.We studied the kinds of enzyme that could catalyze polyester polymerization to take Caprolactone ring opening polymerization, by comparison with the results of experimental, finally selected the Candida Antarctica lipase B as the catalyst of Caprolactone ring opening polymerization,and used the immobilized form of CALB(Novozyme 435) to explored the Caprolactone ring opening’ optimal reaction system of inquiry.Infrared ray diffractometer, Hydrogen nuclear magnetic resonance(1HNMR),X-Raydiffraction(XRD), Scanning electron microscopy (SEM), Differential scanning calorimetry(DSC), Thermal gravimetric analysis(TGA),and gel permeation chromatography(GPC) were used and according to the change of conversion rate and molecular to determine the amount of enzyme in polymerization, polymerization temperature, reaction time, solvent and explored the enzyme catalytic ability for repeat used some times. The results showed that,the amount of enzyme used in reaction have a great influence on the conversion of production,Under the premise of reaction with 10 ml Caprolactone as raw materials,the amount of enzyme was 0.50g could get high conversion production;determine the optimum temperature of the reaction at about 45℃ in the activity of enzyme temperature;it also explored the influence of reaction time,it showed that as the increase of reaction time, molecular weight of the product is gradually increased, and the conversion of product showed a first increased and then has a tendency to reduce,we determined the 24 h as the optimal reaction temperature.We also studied the influence of solvent on the reaction,found that the hydrophobic solvent is more advantageous to the Caprolactone ring opening polymerization.We explored the enzyme catalytic ability for repeat used some times,found that enzyme catalytic properties showed a trend of gradually reduce, but along with the increase in number of catalytic, its catalytic ability decline gradually tend to be stable,which the feasibility of enzyme repeated re-use.We also studied the degradation performance of the PCL catalytic by enzyme, Weightlessness rate and sample weight loss per unit area increased with the increase of the degradation time,The degradation rate of PCL synthetic by Novozyme 435 in solvent-free system show faster than the product of toluene solvent. Overall, the degradation of performance of the PCL which catalytic synthesis by enzyme is superior to the PCL which catalytic synthesis by traditional method of chemical.