Research On Toughening Modification Of Polyvinyl Chloride

As the fact of poor processability and impact-resistance of polyvinyl chloride(PVC),a series of experiments were investigated to obtain an excellent formula of PVC with excellent comprehensive properties and good processability.Influences on processability and mechanical performance of PVC caused by plasticizer like dioctyl phthalate(DOP)and processing aid acrylic copolymer(ACR)were studied in the paper.The result showed that:both DOP plasticizer and ACR processing aid can improve the processability and rheological properties of PVC,and also shorten the plasticizing time.However,the addition of DOP will decrease the comprehensive mechanics performance of PVC;on the contrary,adding processing aid ACR induced negligible decrease.According to the study on mechanical properties of PVC influenced by different proportions of toughening modifier chlorinated polyethylene(CPE)and ACR,the result showed that:with CPE content increased from 0-10 phr,both notched impact strength and elongation at break of PVC/CPE blends tend to increase,but the Young's modulus and tensile strength decreased;with ACR content increased from 0-10 phr,both notched impact strength and elongation at break of PVC/ACR blends increased,Young's modulus kept unchanged,tensile strength increased slightly.Compared with CPE,ACR impact modifier showed better toughened modification effect on PVC,and elongation at break increased more clearly,while Young's modulus and tensile strength kept unchanged.The synergistic toughening effect of CPE and ACR on PVC was studied in the paper,with the total addition amount of CPE and ACR for 6phr,8phr and 10phr,respectively.The result showed that:with the increase of CPE and ACR content,elongation at break of blends increased,Young's modulus and tensile strength slightly decreased as a whole.As the mass ratio of CPE/ACR macthing to 3/3,3/5,and 2/8,respectively,notch impact strength of above-mentioned three series compound formula approached to optimal value respectively,with an outstanding comprehensive performance.Among the three formulae,the blend has best comprehensive properties when mass ratio of CPE/ACR in the blends was 2/8.Scanning electron microscopy(SEM)result showed a typical ductile fracture characteristic.Differential scanning calorimetry(DSC)analysis showed that the compound can also keep a high glass transition temperature.Effect of ultrafine ground CaC03 as filler on the properties of PVC was studied in order to obtain the optimum amount of filler in this paper.5,10,15,20,25 phr CaCO3 were added to PVC blends with 6phr CPE,ACR and CPE/ACR(mass ratio was 2/8),respectively.The result showed that the notched impact strength and tensile strength of blends usually decreased,but Young's modulus and vicat softening temperature increased slightly with the increase of ultrafine ground CaCO3 content.SEM result showed that inorganic filler in the blends dispersed unevenly,aggregation phenomenon can be observed obviously with the increase of ultrafine ground CaCO3 content.Ultrafine ground CaCO3(5,10,15,20,and 25 phr)treated with chelated titanate coupling agent was added to PVC blends with CPE/ACR(mass ratio was 2/8)as synergistic toughening agent.The results showed that the notch impact strength of PVC blends improved significantly after ultrafine ground CaCO3 in the blends was treated,and Young's modulus and processability got better.Scanning electron microscopy(SEM)shows that treated ultrafine ground CaCO3 dispersed well in the organic phase without obvious aggregation Fourier transform infrared(FTIR)spectrum analysis showed that stretching vibration peaks corresponding to the-CH3,-CH2,P-O appeared in treated CaCO3 surface,which indicated organic group was attached to CaCO3 surface,so it will lead to the interaction between polymers.