Study On The Properties Of PVC/NBR Thermoplastic Elastomer

In this text,the effects of heat stabilizer,mass ratio of PVC/NBR,dosage of plasticizer and filler on PVC/NBR thermoplastic elastomer were discussed.To meet the needs of PVC processing,the first part explored the suitable heat stabilizer and its dosage.The results showed that,thermo-gravimetric curves of 175 ?constant temperature showed that,with the decreasing of Ca-Zn dosage and the extension of time,the mass loss rate gradually increased,the initial stage was similer,while the later was apparent.Thermo-gravimetric curves of changing temperature showed that,the sample quality gradually reduced with the extension of time.And along with the increase in dosage of Ca-Zn,the temperature of PVC beginning to "pull chain" removing HC1 gradually raised,to ensure the thermal stability of PVC.Oven heat aging simulated processing conditions,the color of samples were orderly from shallow to deep with the extension of aging time.3 phr Ca-Zn heat stabilizer could meet the experiment condition of blending 5 min at 175 ?.The second part discussed the effects of PVC/NBR mass ratio on the material properties.To ensure the material's high mechanical performance and elasticity,the mass ratio of PVC/NBR was 60/40,The material's hardness was 58 A,tensile strength was 9.6 MPa,elongation at break was 722.6%,100%permanent deformation was 6.9%and 200%permanent deformation was 19%.SEM images showed that,PVC and NBR were mixed well,and their compatibility was good.With the reduce of PVC percentage,NBR ratio increased,the material gradually showed characteristics of rubber.The third part discussed the effects of plasticizer on the properties of PVC/NBR thermoplastic elastomer,including the dosage of DOP,adding methods,volatile,mobility,solvent resistance and the substitutabilityof environmental plasticizer Elvaloy-742.Researches turned out that,with the increase of DOP dosage,products gradually reduced the hardness and tensile strength,permanent deformation first increased and then decreased,and it was minimal when DOP was 60 phr.Along with the increase of DOP dosage,the products'before and after aging glass transition temperature Tg were reducing and the after agingTg had a certain improvement compared with the before aging Tg.Infrared spectrum showed that the absorption peak 1723 cm-1 strengthened and widened gradually.The former indicated that PVC/NBR absorbed more DOP,and the latter showed that the carbonyl O and H atoms formed hydrogen bonds.The graph of plasticizing mechanism showed that the nature of PVC plasticizing is the process of hydrogen bonding formation by C = O of DOP and H-C-Cl of PVC.Fixed total 50 phr DOP,when PVC preplasticated 30 phr,NBR preplasticated 20 phr,it got the best comprehensive performance,and the tensile strength was 10.5 MPa,100%permanent deformation was 3.8%,200%permanent deformation was 17.9%.Increasing the dosage of DOP,volatile rate,mobility and solvent extraction rate all improved.Prolonging the time,the volatile rate,migration rate and solvent extraction rate of DOP will rise gradually.Contrast the plasticizing effect of DOP and Elvaloy-742,with the increase of dosage of them,hardness,tensile strength decreased,permanent deformation rised after the first drop.The effects of two kinds of plasticizers on the material performance before and after aging are different.As a plasticizer,Elvaloy-742 should compound with DOP.When the blending ratio of DOP and Elvaloy-742 is 20/30,the hardness is 72 A,tensile strength is 10.0 MPa,elongation at break is 611.1%and 200%of permanent deformation is 20%,the material's mechanical properties and rebound elasticity are both good,and the distribution effect is good.The fourth part chose four kinds of commonly used fillers to modified the formula,for improving mechanical properties of PVC/NBR thermoplastic elastomer and reducing cost.The results showed that both before and after aging hardness were on the rise,and the after aging hardness enhanced about 2 A.Influence on hardness of CaCO3 and nano-CaCO3 were similar.When CaSO4 and GF dosage exceeds 10 phr,they had greater influence on hardness;Tensile strength of before and after aging were rised first and falled later,the optimum dosage of CaCO3,CaSO4 and GF were about 10 phr,and nano-CaCO3 was about 15 phr.There was a certain rise compared with before aging.With the increase of dosage of four kinds of fillers,before and after aging permanent deformation were on the rise,and the increase of CaCO3,CaSO4 and nano-CaCO3 were lesser.When GF was more than 10phr,it rised a lot.With the increase of filler dosage,gel rate before and after aging reduced.