Synthesis And Application Of Rare Earth Copolymer

Polyvinyl chloride (PVC) is widely used in the world today as one of the synthetic materials which usage is the second of all kinds of materials. But for the poor thermal stability, inferior liquidity of PVC, thermal stabilizers and processing aids must be added into PVC to improve its performance during processing. Rare earth thermal stabilizer is endemic to China, which can inhibit the decomposition of PVC during processing. Acrylate copolymer (ACR) is the most commonly PVC processing aids with good processing properties, excellent weather resistance and high impact strength. In this study, due to the poor thermal stability and processing performance of PVC, organic rare earth copolymer with rare earth elements and acrylic structure was synthesized which can improve the thermal stability and processing performance of PVC.Acrylic rare earth was synthesized first, and organic rare earth copolymer was then synthesized with acrylic rare earth, butyl-acrylate (BA) and methyl-methacrylate (MMA) as monomers by the oxidation reduction methods through aqueous dispersion system polymerization. The optimum experiment plan is the ratio of BA and MMA is 1:1, reaction time is 1.5h, temperature is 55℃, the initiator amount is 2% of the total monomers. The structure of organic rare earth copolymer was characterized by IR. Organic rare earth copolymer with different amount of acrylic rare earth was synthesized by optimum experiment. And Tg of the organic rare earth copolymer was also measured by DSC.Organic rare earth copolymer and the other aids were added into PVC with a certain percentage. And the static stability of the blends was tested by heat oven method and Congo red method respectively. The experiment showed that organic rare earth copolymer can improve the thermal stability of PVC obviously and the more the amount of rare earth, the most the thermal stability of PVC. The processing performance and the mechanical properties were measured by HAAKE rheometer and the universal testing machine respectively. Compared with the traditional thermal stabilizer, organic rare earth copolymer can improve the thermal stability and processing performance of PVC. The processing and mechanical properties of PVC were gradually increased with the organic rare earth copolymer increasing. When the organic rare earth copolymer content was 8 phr, the comprehensive properties were the most. The synergistic effect and weathering resistance were also studied separately.CaSt2 and ZnSt2 were synthesized and the structure was also inspected by IR. The optimum proportion of CaSt2 and ZnSt2 was studied by the static stability experiment. And when the ratio of CaSt2 and ZnSt2 was 3:1, thermal stability of PVC was the best. So the composite system of CaSt2:ZnSt2=3:1 was as the Ca/Zn compound additive. The thermal stability, processing performance and the mechanical property of PVC was the best when the ratio of organic rare earth copolymer and Ca/Zn was 3:1 by the static stability measurement, the rheological and mechanical properties measurement.Organic rare earth copolymer was remixed lead stearate and modification effect of composite stabilizers on PVC was studied. Compared with organic rare earth copolymer and lead stearate separately, organic rare earth copolymer-lead stearate composite modification system has excellent thermal stability by static stability measurement. The more organic rare earth copolymer of the composite system, the smallest the tensile strength but the elongation at break increasing significantly. When organic rare earth copolymer was added into the modification system, the melt viscosity of the blends was low, and has good fluidity and the system was easy to plasticize, and also has excellent processing performance.