注塑用聚丙烯化学发泡专用料的研制与性能

Development and Properties of Polypropylene Chemical Foaming Special Materials for Injection Molding

将PP/LDPE共混物、硬脂酸改性碳酸氢钠(Na HCO3)与纳米碳酸钙(纳米Ca CO3)作为原料,采用闭模发泡注塑工艺制备了聚丙烯(PP)化学发泡专用材料。通过熔体流动速率(MFR)、热重分析(TG)与扫描电镜(SEM)对其进行了表征,研究了硬脂酸对碳酸氢钠分解温度的影响,熔体强度、改性碳酸氢钠与成核剂对减重率与力学性能的影响。结果表明,硬脂酸与碳酸氢钠按照1∶2的比例加入,使初始分解温度提高到184℃,分解区间为184~199℃,熔体强度与改性碳酸氢钠用量的提高均可使发泡试样的减重率增大,成核剂的加入提高了发泡试样的冲击强度。当加入改性Na HCO32. 5份,成核剂Ca CO32份,LDPE 20份时,减重率为9. 25%,冲击强度为32. 7 k J/m2,与未发泡材料的冲击强度(23. 8 k J/m2)相比,提高了37. 4%。

Polypropylene(PP)chemical foaming special materials were prepared by PP/LDPE blend,stearic acid modified sodium bicarbonate(NaHCO3)and nanometer calcium carbonate(nano CaCO3).The melt flow rate(MFR),thermogravimetric analysis(TG)and scanning electron microscopy(SEM)were used to characterize the effect of stearic acid on the decomposition temperature of sodium bicarbonate and the effect of melt strength,modified sodium bicarbonate and nucleating agents on weight loss rate and mechanical properties.The results showed that stearic acid and sodium bicarbonate were added at 1:2 to increase the initial decomposition temperature to 184℃,the decomposition interval was 184~199℃,and the increase of melt strength and the amount of modified sodium bicarbonate increased the weight loss rate of the foamed sample,and the nucleating agent was added to increase the impact strength of the foamed sample.When the modified NaHCO3 was 32.5 parts,the nucleating agent CaCO3 was 2 parts,and the LDPE was 20 parts,the weight loss rate was 9.25%,the impact strength was 32.7 kJ/m2,which was 37.4%higher than the impact strength of the unfoamed material of 23.8 kJ/m2.