接枝聚乙烯/改性SiO_2共混物的结构及性能

Structure and Properties of Grafted Polyethylene/Modified SiO_2 Blends

通过预辐照接枝和悬浮接枝技术制备流滴树脂复配物和纳米SiO_2与流滴剂司班(SP)接枝物SiO_2-g-SP的共混物。采用红外光谱、差示扫描量热分析、扫描电子显微镜、旋转流变仪、加速流滴测试仪、材料试验机及液滴形状分析仪对共混物的结构、性能进行了表征。结果表明,SiO_2-g-SP相比改性纳米SiO_2在2920 cm^(-1)、2850 cm^(-1)、1728 cm^(-1)、1456 cm^(-1)和722 cm^(-1)出现了新的特征吸收峰。其中1728 cm^(-1)是酯类羰基的特征峰,2920 cm^(-1)和2850 cm^(-1)处的峰为碳氢键不对称和对称伸缩振动特征峰,这说明SP已接枝到了改性纳米SiO_2表面。通过改性纳米SiO_2接枝SP的方法引入SiO_2,使得共混物熔融温度降低,结晶温度升高;流滴剂与聚乙烯相容性变好,容易加工;共混物流滴性能得到改善,流滴期最多延长6 d,力学性能得到改善,拉伸强度最多提高了2. 5 MPa。

The blends of dropping compound and nano-silica grafted dropping agent SP （SiO2-g-SP） were prepared by pre-irradiation and suspension grafting techniques. The structure and properties of the blends were characterized by 1H-NMR, DSC, SEM, rotary rheometer, accelerated flow tester, material testing machine and droplet shape analyzer. The results show that SiO2-g-SP exhibits new characteristic absorption peaks at 2920 cm-1, 2850 cm-1, 1728 cm-1, 1456 cm-1 and 722 cm-1 compared with modified nano-SiO2. The peak at 1728 cm-1 is the characteristic peak of the ester carbonyl,- and the peaks at 2920 cm-1 and 2850 cm-1 are the asymmetric and symmetrical stretching vibration peaks of the hydrogen：bond, which indicates that the SP is successfully grafted onto the surface of the modified nano-SiO2. SiO2 is introduced in linear low density polyethylene （LLDPE） through grafting SIO2. The melting temperature of the blends is decreased and the crystallization temperature is increased. The,compatibility of the dropping agent with the polyethylene is improved and the blends are easily to process; the dropping properties of the blends are improved and the best one is increased by 6 d. The mechanical properties are improved and the tensile strength of the best one is increased by 2.5 MPa.