Research On Synthesis And Application Of Non-phthalate Environmental Plasticizers

As one of the most common polymers,polyvinyl chloride(PVC)has been widely used in food,construction,medical and other fields due to its low price and excellent performance.Plasticizer is an indispensable processing aids in the production of flexible PVC products to reduce the glass transition temperature and improve the flexibility of the polymer.At present,the most widely used phthalate plasticizer on the market is dioctyl phthalate(DOP).However,studies have proved that phthalate plasticizers have certain toxicity to humans and animals,so it has been restricted in many fields such as medical supplies and children’s toys.With the enhancement of the people’s concept of environmental protection,people also pay more attention to the use safety of materials in close contact.Therefore,it is an inevitable trend of development to shift from the traditional petroleum-based phthalate plasticizer to a safer new type of high-efficient non-phthalate environmental plasticizer.There is a great demand for plasticizers in the Chinese market.The transition from phthalate to current environment-friendly terephthalate plasticizers is the demand of the current market.In the long term,it is not only a way to promote the rational use of resources,but also an inevitable direction for the development of the plasticizing industry to modify and prepare environment-friendly plasticizers from renewable biomass raw materials.In this paper,according to the molecular structure,a series of high-efficiency environment-friendly plasticizers were prepared to use terephthalic acid,rininoleic acid and vegetable oleic acid as raw materials.At the same time,compared with those commercial plasticizers,the performance of PVC with different plasticizers was summarized and analyzed,then the action mechanism of plasticizers in PVC matrix was speculated,and it is expected to effectively replace the current traditional phthalate plasticizer.Di(2-propylheptyl)terephthalate(DPHTP)was synthesized from petroleum terephthalic acid and 2-propylheptanol by one-step esterification.Subsequently,the structure and quantitative analysis of DPHTP were teseted by FT-IR,~1H NMR and GC-MS.The commercial main plasticizer DOP and dioctyl terephthalate(DOTP)were selected for comparison to prepare PVC samples,and the plasticizing properties of different PVC samples were evaluated.The results showed that compared with DOP and DOTP,PVC with DPHTP had higher elongation at break,thermal stability and better electrical properties.In addition,the heating reduction of DPHTP was 0.0319%,which was only half of DOTP and one eighth of DOP,showing extremely low volatility resistance.A bio-based environment-friendly plasticizer,acetylated 1,8-octanediol di rininoleic acid levulinate(A-ODL)was prepared through esterification,epoxidation and ring-opening acetylation with a renewable ricinoleic acid from non-edible oil,1,8-octanediol and levulinic acid.The molecular structure of the plasticizer was verified by FT-IR and ~1H NMR,and the commercial DOP,DOTP and dioctyl adipate(DOA)were used for comparison.The results showed that the initial decomposition temperature of PVC plasticized by A-ODL was 38°C higher than that of DOA and DOP,which greatly improved the thermal stability of PVC.In addition,compared with three commercially plasticizers,the PVC samples with A-ODL not only showed excellent flexibility,but also showed excellent extraction resistance and safety in four kinds of migration resistance and food simulants.From the structural analysis,A-ODL was derived from renewable ricinoleic acid,which could significantly improve the thermal stability,mechanical properties,and extraction resistance of the PVC materials.Acetylated triethylene glycol dioleate(AOT)with excellent mechanical properties was prepared through a three-step reaction using triethylene glycol and oleic acid as the main raw materials.It was compared with commercial DOA with similar long chain structure and DOTP in the market to prepare different PVC samples,and the performance of different PVC samples was studied.The results showed when the plasticizer content was the same,the elongation at break of PVC with AOT was 697.7%,which showed the better flexibility.In addition,the prepared AOT showed excellent thermal stability.In dynamic thermo-mechanical analysis,it could also significantly reduce the Tg of PVC materials.In the range of visible light wavelength,PVC films with AOT also showed excellent transparency.Compared with the previous plasticizer prepared in the system,AOT,which had more flexible chain segments,was superior to commercial DOA and DOTP in mechanical properties and optical properties.It could be used in flexible PVC products with high requirements.With cyclohexanol and ricinacid as the raw material,a multifunctional bio-based environment-friendly plasticizer acetylated cyclohexanol acetylcastor oleate(A-CAE)was prepared through esterification,epoxidation and acetylation.DOTP and tributyl acetyl citrate(ATBC)were also selected as contrast plasticizers to compare the performance,and A-CAE and DOTP were compounded to explore the synergistic plasticizing effects.The results showed that A-CAE had higher boiling point and thermal stability,which could significantly delay the dechlorination of PVC.In addition,PVC plasticized with A-CAE showed good compatibility,when the amoun of plasticizer was 50,the Tg of PVC with A-CAE decreased to 32.2°C,and the transmittance in the visible light range also reached 90.5%,which was far more than the PVC with petroleum-based plasticizers on the market.The mechanical property showed that the elongation at break of the sample with A-CAE reached 740.5%,which was 40.4%higher than ATBC,indicating a softer performance.In various tests of extraction resistance,volatilization resistance and low temperature,A-CAE also showed excellent stability.When A-CAE and DOTP were blended to plasticize PVC,the obtained samples also showed good synergistic and plasticizing effect.Inspired by the free volume theory,it was found that six-membered rings and multiple polar groups were introduced in A-CAE,and all the PVC with A-CAE had excellent comprehensive performance,which provided a new choice for the design and application of bio-based environment-friendly plasticizers.