Zhang Yeli, Chu Chih-Chang
Fiber and Polymer Science Program, Department of Textiles and Apparel, Cornell University, Ithaca, NY 14853-4401, USA.
J Mater Sci Mater Med. 2002 Aug;13(8):773-81. doi: 10.1023/a:1016123125046.
The thermal and mechanical properties of a new family of biodegradable hydrogels made of photocrosslinked dextran derivative of allyl isocyanate (dex-AI) and poly (D,L) lactide diacrylate macromer (PDLLAM) were studied. The changes of thermal and mechanical properties of the dex-AI/PDLLAM hydrogels as functions of dex-AI to PDLLAM composition ratio and immersion time in phosphate buffer solution at 37 degrees C were also investigated. Thermal property data showed that the chemical modification, crosslinking, swelling and hydrolytic degradation affected the glass transition and melting temperatures. Based on thermal data, no phase separation was observed in the bicomponent dex-AI/PDLLAM hydrogels. Mechanical property data showed that, by changing the composition ratio, dex-AI/PDLLAM hydrogels having a wide range of dry and swollen compression moduli could be obtained. The moduli of the dex-AI/DPLLAM hydrogels in dry state decreased with an increase in the PDLLAM composition due to the reduction in glass transition temperature of the hydrogels. The loss of mechanical strength in buffer solutions was attributed to the swelling-induced formation of 3D porous network structure in the early stage of immersion and the hydrolytic degradation of the PDLLAM in the late stage via the chain scission of ester linkages located in the PDLLAM backbone. Because swelling and degradation were composition dependent, the magnitude of the loss of mechanical strength was also composition-dependent.
研究了由异氰酸烯丙酯的光交联葡聚糖衍生物（dex-AI）和聚（D，L）丙交酯二丙烯酸酯大分子单体（PDLLAM）制成的新型可生物降解水凝胶的热性能和力学性能。还研究了dex-AI/PDLLAM水凝胶的热性能和力学性能随dex-AI与PDLLAM组成比以及在37℃磷酸盐缓冲溶液中的浸泡时间的变化。热性能数据表明，化学改性、交联、溶胀和水解降解影响了玻璃化转变温度和熔点。基于热数据，在双组分dex-AI/PDLLAM水凝胶中未观察到相分离。力学性能数据表明，通过改变组成比，可以获得具有广泛干态和溶胀压缩模量的dex-AI/PDLLAM水凝胶。由于水凝胶玻璃化转变温度的降低，干态下dex-AI/DPLLAM水凝胶的模量随PDLLAM组成的增加而降低。缓冲溶液中机械强度的损失归因于浸泡初期溶胀诱导的三维多孔网络结构的形成以及后期PDLLAM通过位于PDLLAM主链中的酯键的链断裂而发生的水解降解。由于溶胀和降解取决于组成，机械强度损失的程度也取决于组成。
