抗紫外PC/PMMA交替微层复合薄膜的制备与性能

为提高聚碳酸酯(PC)/聚甲基丙烯酸甲酯(PMMA)复合薄膜的抗光老化性能,选用具有高紫外线吸收能力的苯并三唑紫外线吸收剂(UV–P)作为PC的改性剂,并通过自制的微纳层叠装置制备出抗光老化的PC/PMMA复合薄膜。首先,利用双螺杆的剪切分散作用将不同添加量的UV–P与PC熔融共混并挤出造粒;然后,改性的PC与PMMA经自制的微纳层叠共挤装置挤出成型,制备复合薄膜;最后,对复合薄膜的结构和性能进行了表征。结果表明,具有有机小分子结构的UV–P在熔融态下能与聚合物材料有着良好的相容性;UV–P的加入对复合薄膜总失重率的影响并不大,但对复合薄膜第一阶段的热失重影响较大,在UV–P填充量为0.15%和0.8%时,复合薄膜的第一次热失重率由45.46%分别下降到36.79%和35.08%;在UV–P的填充量为0.35%时,复合薄膜在沿挤出方向及垂直于挤出方向的拉伸强度最大,分别达到72.2,52.4MPa,同时沿挤出方向上的断裂伸长率也达到最大值,为11.8%;随着UV–P填充量的增加,复合薄膜的紫外线吸收率也逐渐提升,在UV–P的填充量为0.5%时,复合薄膜的光学性能最佳,可以屏蔽99%的380nm以内的紫外线,并且平均透光率达到了82.1%的较高水平。

Preparation and Properties of Ultraviolet Resistant PC/PMMA Alternating Micro-layer Composite Films

In order to improve the anti-photoaging properties of PC/PMMA composite films,benzotriazole ultraviolet absorbent (UV–P) with high ultraviolet absorption capacity was selected as the modifier of PC,and anti-photoaging PC/PMMA composite films were prepared by self-made micro-nano cascade co-extrusion device. Firstly,UV–P and PC with different additions were melted and blended by twin-screw shear dispersion and extruded to granulate. Then,the modified PC and PMMA were extruded by micro-nano laminated co-extrusion device to prepare composite films. Finally,the structure and properties of composite films were characterized. The results show that UV–P with organic small molecular structure has good compatibility with polymer materials in molten state;the addition of UV–P has little effect on the total weight loss of composite films,but has great influence on the thermal weight loss of composite films in the first stage. When the filling amount of UV–P is 0.15% and 0.8%,the first heat loss of composite films is significant. The weight ratio decreases from 45.46% to 36.79% and 35.08% respectively. When the filling amount of UV–P is 0.35%,the tensile strength of composite film along the extrusion direction and perpendicular to the extrusion direction reaches 72.2 MPa and 52.4 MPa respectively,and the elongation at break along the extrusion direction reaches the maximum value of 11.8%. With the increase of filling amount of UV–P,the ultraviolet absorption of composite film is the highest. The optical properties of alternating micro-layer PC/PMMA composite films are the best when the filling amount of UV–P is 0.5%. It can shield 99% of the ultraviolet radiation within 380 nm,and the average transmittance reaches a high level of 82.1%.