两种弹性体对PPR材料低温抗冲击性能的影响

Effect of Two Types of Elastomers on Low Temperature Impact Resistance of PPR Materials

无规共聚聚丙烯(PPR)管材作为一种新型绿色建筑材料,被广泛应用在民用建筑和工业给排水设施等方面,但由于PPR耐热性和耐低温冲击性能较差,限制了应用,因此提高PPR的韧性尤其是低温韧性成为研究的重点。以PPR为基体,通过挤出机造粒、注塑机成型等手段与聚烯烃弹性体POE、聚苯乙烯弹性体TPE两种不同的增韧剂共混并进行研究,分析了不同配方对二元共混体系的拉伸强度、断裂伸长率、缺口冲击韧性以及低温冲击性能的影响;通过DSC、XRD、冲击试验机等仪器设备研究PPR复合材料的熔融结晶性能和力学性能。根据研究结果,得到耐低温抗冲击性能较为理想的PPR复合材料最优增韧方法。结果表明:随着弹性体TPE、POE用量的增加,在室温、0、-15和-25℃时共混体系的缺口冲击强度都有所增强。与POE相比较,弹性体TPE对PPR的增韧作用尤为明显,TPE填量为15%时,PPR/TPE共混料的冲击韧性最理想,体系的断裂伸长率增幅更大,其综合力学性能最好,改性材料常温冲击强度较纯PPR提高82.5%,低温0、-15、-25℃冲击强度分别增加9.25、9.13、8.53 k J/m^2,断裂伸长率由279.62%增加到584.53%,而拉伸强度仅仅降低3.43 MPa。

Polypropylene random copolymer （PPR） pipe as a new green building material is widely used in civil construction and industrial water supply and drainage facilities, and so on. But the insufficient low temperature impact performance of PPR limits its application. Polyolefin elastomer （POE） and polystyrene elastomer （TPE） as toughening agents were used to conduct the research. The tensile strength, elongation at break, notch impact strength of the two blend systems were analyzed with different formulas, and machanical properties and melting crystalline of the PPR/elastomer composites were researched by differential scanning calorimeter, X-ray diffraetometer and impact testing machine, etc. According to the research results, the best toughening method of PPR composite material with low temperature resistance was obtained. The results show that the notched impact strength at room temperature and low temperature are increased with the increase of the elastomer amount. Compared with POE, the toughening effect of TPE is better. When the filling amount of TPE is 15%, the impact toughness of PPR/TPE blends is the best, the elongation at break increased more, and the comprehensive performance is the best. Specifically, compared to pure PPR, the modified PPR/TPE material has increased impact strength values-room temperature impact strength increased by 82.5%, low temperature impact strength increased by 9.25 kJ/m2 at 0℃, 9. 13 kJ/ m2 at -15℃, 8.53 kJ/m2 at -25 ℃, respectively; and its breaking elongation increases from 279.62% to 584. 53%, while the tensile strength reduces by 3.43 MPa.