CAJ | 학술논문

以N-异丙基丙烯酰胺( NIPAAm)为单体，二苯甲酮( BP)为光敏剂，过硫酸胺( APS)为自由基引发剂，采用溶液中光接枝方法制备了具有温度敏感特性的聚氨酯微球( PUS)。傅里叶变换红外光谱( FTIR)和扫描电子显微镜( SEM)结果表明，在聚氨酯微球表面形成了聚异丙基丙烯酰胺( PNIPAAm)接枝聚合物层。在接枝过程中，延长反应时间与增加引发剂浓度均有利于提高接枝率。常温下，接枝率随反应时间延长呈线性增长，当反应时间超过40 min后，接枝率基本保持稳定；而引发剂浓度对接枝率的影响存在最佳优化值，即其浓度为单体质量分数的3%。采用差示扫描量热法( DSC)对接枝改性前后聚氨酯微球的温敏特性进行分析表征，证实改性后的微球在35℃左右出现低临界互溶温度( LCST)，在此温度附近表现出对温度敏感特性。接触角测试与溶胀测试结果表明，在低临界互熔温度以下，接枝改性的聚氨酯微球具有良好的亲水性。
이N-이병기병희선알( NIPAAm)위단체，이분갑동( BP)위광민제，과류산알( APS)위자유기인발제，채용용액중광접지방법제비료구유온도민감특성적취안지미구( PUS)。부리협변환홍외광보( FTIR)화소묘전자현미경( SEM)결과표명，재취안지미구표면형성료취이병기병희선알( PNIPAAm)접지취합물층。재접지과정중，연장반응시간여증가인발제농도균유리우제고접지솔。상온하，접지솔수반응시간연장정선성증장，당반응시간초과40 min후，접지솔기본보지은정；이인발제농도대접지솔적영향존재최가우화치，즉기농도위단체질량분수적3%。채용차시소묘량열법( DSC)대접지개성전후취안지미구적온민특성진행분석표정，증실개성후적미구재35℃좌우출현저림계호용온도( LCST)，재차온도부근표현출대온도민감특성。접촉각측시여용창측시결과표명，재저림계호용온도이하，접지개성적취안지미구구유량호적친수성。
Surface modification of polyurethane microspheres( PUS) by grafting poly( N-isopropylacrylamide) ( PNIPAAm) was initiated under UV light. Besides benzophenone( BP) was used as a photosensitizer, ammo-niumperoxydisulfate( APS) was used as a free radical initiator. The occurrence of grafting copolymerization of PNIPAAm was testified by the attenuated total multiple reflection technique( ATR-IR) . Scanning electron mi-crograph( SEM) showed that the surface morphology of PUS changed significantlyafter modification. The lower critical solution temperature(LCST) of the PUS was determined by differential scanning calorimetry(DSC), and the wettability of the membrane assembled by PU microspheres was investigated by water contact angle measurement. The results showed that the grafting yield increased with irradiation time and finally reached the saturation value. As the concentration of APS initiator was increased, the grafting yield had a maximum. In addition, the modified PU microspheres were thermosensitive similar to that of PNIPAAm gel, and the LCST was determined about 35 ℃. The water contact angle measurement proved that the PNIPAAm-g-PU micro-spheres demonstrated good hydrophilic behavior below the LCST.