Interpenetrating polymer networks (IPN) of polyurethane (PU) and polystyrene (PS), which contain quaternary ammonium salt formation groups, i.e., N-methyl diethanol amine (MDEA) and chloromethyl styrene (CMS), respectively, were syntheslzed through simultaneous polymerization. Phase separation behaviors were investigated using a light scattering apparatus and final morphologies were observed by scanning electron microscope (SEM). Glass transition temperature (T_g) behaviors were also studied using a dynamic mechanical analyzer. As the content of MDEA in PU and CMS in PS was increased, the rate of phase separation was decreased. In case that the content of MDEA and CMS in IPN exceeded a critical amount, scattered light was not detected due to the intermolecular mixing effect. As the content of reactant for internetwork salt formation was increased, the size of dispersed phase was decreased and the domain showed better dispersion in the SEM observations. These morphological variation agree well with the light scattering data. As the content of MDEA and CMS in IPN was increased, T_g showed an inward shift for both components and two distinct peak was gradually merged into a single broad peak.

N-methyl diethanol amine(MDEA)을 사슬연장제의 한 성분으로 갖는 폴리우레탄과 MDEA와 반응하여 4급 암모늄염을 형성시킬 수 있는 클로로메틸스티렌 (CMS) 성분이 소량 함유된 폴리스티렌을 조성고분자로 하는 IPN을 동시중합법으로 제조하였다. IPN 합성과정에서의 상분리 현상을 광산란 장치로 조사하였고, 최종 몰폴로지 거동을 SEM 관찰 및 dynamic mechanical analyzer :DMA) 측정을 통하여 검토하였다. MDEA와 CMS의 함량이 증가함에 따라 상분리 속도가 감소되는 경향을 보였으며, 특정 조성에서는 산란광이 검출되지 않을 정도의 높은 혼화성을 보이는 경우도 있었다. 최종 몰폴로지 거동 역시, MDEA와 CMS의 함량이 증가함에 따라 보다 미세하고 균일한 분산상이 얻어지고, 유리전이온도(T_g)가 안쪽으로 이동하며 완만해지는 경향을 보여 합성시의 상분리 거동과 잘 일치하는 결과가 얻어졌다.

Keywords: interpenetrating polymer networks; phase separation; light scattering; internetwork salt formation; chloromethyl styrene