Preparation And Properties Of Green Plasticizer Based On Vegetable Oil

As an important engineering plastic,polyvinyl chloride(PVC)is widely used in various fields with its excellent performance and low price.Plasticizers play an important role in flexible PVC products.At present,the most widely used plasticizer product in the market is phthalate plasticizer whose raw material comes from petroleum.However,phthalates have carcinogenicity and reproductive toxicity,and are easy to migrate from PVC matrix,thus posing a threat to human health and environment.Therefore,they are gradually restricted to some areas by various countries.In addition,according to the current consumption rate of oil,the oil reserves in the world are only enough for 50 years.Therefore,it is an ideal and feasible way to solve these problems by using renewable biomass as raw materials to synthesize efficient and environmentally friendly bio-based plasticizers.In this paper,according to the molecular structure design of plasticizers,a series of efficient and sustainable vegetable oil-based environmental plasticizers were synthesized from fatty acids derived from waste oil and oleic acid derived from vegetable oil as the main raw materials.Compared with commercial plasticizers,the performances of PVC samples were tested to explore the effect of different plasticizer molecular structure on the performance of PVC.In addition,the potential plasticizing mechanism of the synthesized plasticizer was discussed.Acetylated fatty acid methyl ester trimellitic acid ester(AC-FAME-TAE)was synthesized by esterification,epoxidation,ring opening esterification and acetylation of fatty acid from waste oil.The structure of plasticizer was analyzed by FT-IR and ~1H NMR.The properties of PVC samples plasticized by these plasticizers were tested and compared with that of di(2-ethylhexyl)phthalate(DOP)and epoxy fatty acid methyl ester(EFAME).The results showed that AC-FAME-TAE had better thermal stability,volatile resistance and extraction resistance than DOP and EFAME.The initial decomposition temperature(T_i)of PVC samples plasticized by AC-FAME-TAE was 10°C and 39.3°C higher than that plasticized by DOP and EFAME at the same plasticizer content.Acetylated fatty acid methyl ester malate(AC-FAME-MAE)was synthesized by esterification,epoxidation,ring opening esterification and acetylation of fatty acid and DL-malic acid from waste oil.The structure of the plasticizer was verified by FT-IR and ~1H NMR.Similarly,DOP and EFAME were used as the contrast plasticizers,and then a series of tests were carried out on PVC samples.The results showed that the molecular structure of AC-FAME-MAE was more flexible than the plasticizer synthesized in the previous system.The plasticizing efficiency of AC-FAME-MAE was 98.8%,and the comprehensive mechanical properties of plasticized PVC were better than those of PVC specimens plasticized by two contrast plasticizers.In addition,the PVC specimen plasticized by AC-FAME-MAE had better thermal stability,migration resistance and extraction resistance.The comprehensive application performance of AC-FAME-MAE was more comprehensive than that of the plasticizer in the previous work.Using oleic acid as acid source,1,4-cyclohexanedimethanol,1,8-octanediol and 1,6-hexanediol as alcohol sources,three kinds of ester branched epoxy oleate plasticizers(EB-ECDD,EB-EODD and EB-EHDD)were obtained by esterification,Claisen condensation and epoxidation.The molecular structure of plasticizer was verified by FT-IR and ~1H NMR.Di(2-ethylhexyl)terephthalate(DOTP)and di(2-ethylhexyl)adipate(DOA)were selected as contrast plasticizers.The properties of PVC specimens plasticized by these plasticizers were tested.According to the results,the plasticizing efficiency of PVC specimens plasticized by these three plasticizers was 15%-24%higher than that plasticized by DOTP.The three kinds of PVC samples also had excellent migration resistance,and the mass loss rate of these PVC samples in three solvents was less than 3.2%in the 10-day extraction resistance test.In addition,the migration rate of the three kinds of PVC samples in food simulation solution did not exceed the safety threshold,and the migration rate of PVC test pieces plasticized by EB-ECDD in oily environment was only 0.6%.The application performance of the three plasticizers was more comprehensive than that of the previous plasticizers,and the plasticized PVC had a great breakthrough in the migration resistance.The structure of plasticizer and properties of PVC were concluded.It was found that the six membered cycloalkane structure of plasticizer had higher plasticizing efficiency than the straight chain structure,and it could also improve the migration resistance of PVC.To a certain extent,appropriately increasing the molecular weight of plasticizer can improve the thermal stability,overall mechanical properties and migration resistance of PVC.But at the same time,it will reduce the plasticization efficiency and make the flexibility of PVC worse.Four kinds of cold resistant plasticizers(E-CDD,A-CDD,E-ODD and A-ODD)were synthesized by esterification,epoxidation and open-loop acetylation reaction with oleic acid as the acid source,1,4-cyclohexane dimethyl alcohol and 1,8-octyl glycol as the alcohol source.The molecular structure of plasticizer was verified by FT-IR and ~1H NMR.Similarly,with DOTP and DOA as contrast plasticizers,a series of tests were carried out on various properties of PVC samples.According to the results of performance test,the PVC plasticized by the four plasticizers had similar thermal stability under the same content of 50 phr plasticizer,and their T_i were about 20°C and 40°C higher than that plasticized by DOTP and DOA,respectively.The migration resistance of the four kinds of PVC samples was also excellent.The migration rate of the four kinds of PVC samples in water-based,alcoholic and acidic food simulants was less than 2%,and the migration rate of the four kinds of PVC samples in oily environment was also less than 5%of the safety threshold.Among them,the PVC sample plasticized by E-CDD had the best transparency,and its elongation at break was 145%and 15.2%higher than that of DOTP and DOA with the same 50 phr plasticizer.In addition,the T_g of the PVC sample plasticized by E-CDD was 10°C lower and the plasticizing efficiency was 16.9%higher than that of PVC plasticized by DOTP.The low temperature efficiency values of the four cold resistant plasticizers were closed,which were about 25°C higher than DOTP and 15°C higher than DOA.Their freezing points were between DOTP and DOA,which indicated that the four plasticizers could still keep good plasticizing effect at low temperature,and the plasticized PVC material had excellent cold resistance.Compared with the previous synthesis of some plasticizers,the four cold resistant plasticizers not only had good comprehensive properties,but also had good plasticizing effect in cold environment.According to the structure of plasticizer and the properties of PVC,it is found that the structure of six membered cycloalkanes in plasticizer can improve the thermal stability,migration resistance and cold resistance of PVC more than the straight chain structure,but its mechanical properties will decrease slightly.When one epoxy bond in the structure of E-CDD is transformed into two ester groups,the mechanical properties and migration resistance of the plasticized PVC can be partially improved,but the cold resistance will be slightly weakened.