紫外光引发低密度聚乙烯接枝聚N-异丙基丙烯酰胺的温敏改性

Low-Density Polyethylene-Grafted Poly (N-isopropyl acrylamide) Initiated by UV Irradiation

以二苯甲酮(BP)为光敏剂,采用两步表面光接枝法将N-异丙基丙烯酰胺(NIPAAm)单体接枝到低密度聚乙烯(LDPE)表面,赋予LDPE表面温敏性。通过红外光谱和扫描电子显微镜等对LDPE-g-PNIPAAm的结构进行了表征;采用调制差示扫描量热分析技术和表面水接触角测定法研究了LDPE-g-PNIPAAm的温敏性;讨论了引发剂浓度、光还原时间、单体浓度和光照时间对接枝率的影响。结果表明,LDPE-g-PNIPAAm具有温敏亲/疏水性,其低临界溶解温度(LCST)在33℃左右。增加引发剂浓度、单体浓度、延长光还原时间和光照时间都能使接枝率增加;且可以通过调节这4种因素来控制接枝率。

Benzophenone（BP） was used as photoinitiator, and N-isopropylacrylamide （NIPAAm） was grafted onto the surface of low-density polyethylene（LDPE） by two steps photografting polymerization, given the LDPE surface thermoresponse. The structures of LDPE-g-PNIPAAm were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy （SEM）. Thermoresponse of LDPE-g-PNIPAAm was studied by modulated differential scanning calorimetry （MDSC） and water contact angle measurements. The effects of initiator concentration, photo reduction time, monomers concentration, as well as UV light irradiation time on the grafting ratio were discussed. The results show that LDPE-g-PNIPAAm has a thermoresponsive hydrophilicity/ hydrophobicity with lower critical solution temperature （LCST） at about 33 ℃. The grafting ratio is improved with increasement of the initiator concentration, photo reduction time , monomers concentration, and UV light irradiation time, which can be controlled by adjusting these four factors.