Preparation And Properties Of ACM/HPVC Thermoplastic Elastomer

Acrylate rubber(ACM)is an elastomer obtained by copolymerizing acrylate as a main monomer.Its main chain is a saturated carbon chain,and its side groups are polar ester groups.The special chemical structure provides ACM many excellent characteristics,such as heat resistance,aging resistance,oil resistance,ozone resistance,ultraviolet resistance,etc.The mechanical properties of ACM are superior to those of fluorine rubber and silicone rubber,and its heat resistance,aging resistance and oil resistance are also superior to those of nitrile-butadiene rubber.But it also has many defects such as sticking stick,sticking mould,contaminating mould and so on.HPVC usually refers to PVC resin with an average degree of polymerization of more than 1700.Its greatest characteristic is that plasticizer is absorbed a lot by HPVC.Its soft products not only maintain the original properties of general-purpose PVC resin,but also are superior to general-purpose PVC resin in oil resistance,abrasion resistance,corrosion resistance,weather resistance,cold resistance,ozone resistance and other aspects.If HPVC could be combined with ACM rubber,the new materials not only having some of characteristics of ACM rubber,but also the low energy consumption,low cost and recyclability would be expected to be prepared,for example,TPE and TPV.In this paper,the preparation and properties of ACM/HPVC TPE and ACM/HPVC TPV were studied using polyvinyl chloride and acrylate rubber as main raw materials,911 P as a plasticizer,OPE as a lubricant,1010 and 168 as an antioxidant,and calcium-zinc stabilizer as auxiliaries.ACM/HPVC TPE and ACM/HPVC TPV of different ACM rubber types were prepared by torque rheometer and twin-screw extruder.Firstly,it was found that epoxy ACM/HPVC TPE had the best comprehensive performance and carboxylic ACM was the best choice for ACM/HPVC TPV.Secondly,the effect of the molecular weight of PVC,the rubber-plastic ratio and the amount of compatibilizer on the properties of ACM/HPVC TPE was investigated by a twin-screw extruder.The results showed that with increasing molecular weight of PVC,the comprehensive mechanical properties,aging resistance and heat-resistant oil of ACM/HPVC TPE materials increased,but the resilience decreased and the difficulty in processing increased.With the increase in rubber-plastic ratio,the tensile strength,elongation at break,tear strength,hardness and flowability of ACM/HPVC TPE decreased,while the properties such as resilience,heat-resistant oil and hot air aging were improved.ACM/HPVC TPE was homogeneous macroscopically,whereas the phase separation existed microscopically,and increased obviously with increasing the rubber-plastic ratio.With the increase of compatibilizer dosage,the comprehensive properties and heat-resistance oil performance of the materials were rapidly improved,and these properties increased slowly when the dosage of compatibilizer exceeded 20%.According to the analysis of scanning electron microscopy(SEM),the optimum amount of adding VC-g-AC was 20% of theamount of adding ACM rubber.The decomposition temperature and weight loss rate of ACM/HPVC TPE were not affected basically by the molecular weight and compatibilizer of PVC.Thirdly,the effect of curing system,amount of curing agent,rubber-plastic ratio,curing temperature,rotating speed and curing time on the properties of ACM/HPVC TPV were investigated by torque rheometer and twin-screw extruder.The results showed that polyethyleneimine was a best vulcanizing agent for ACM/HPVC TPV,and its optimum dosage was 1% of the amount of ACM rubber.With the increase of rubber-plastic ratio,the tensile strength of ACM/HPVC TPV decreased first and then increased,and reached the lowest value when the rubber-plastic ratio was 1:1;The elongation at break,heat aging resistance,heat-resistance oil performance and thermal decomposition were enhanced;Compression deformation rate,hardness and tear strength decreased gradually.Considering the processability in industrial production and the comprehensive properties of ACM/HPVC TPV,the best rubber-plastic ratio of dynamic vulcanization was 3:2.Fourthly,since the torque rheometer itself was limited by the weak shear force,low automation degree and poor self-cleaning ability,the preliminary results of exploring the processing technology of ACM/HPVC TPV by the torque rheometer were as follows: the comprehensive performance of PVC/ACM-TPV at the vulcanization temperature of170-190 °C was relatively stable,and the performances of ACM/HPVC TPV within the rotational speed of 70 r/min to 140 r/min did not changed much.Twin-screw extruder was the best equipment for industrial production of ACM/HPVC TPV.The optimum setting temperature for producing ACM/HPVC TPV was 180 °C(average temperature),and the optimum screw speed was 250 r/min.