高力学强度羟乙基纤维素/聚丙烯酸复合水凝胶的制备

Preparation of Hydroxyethyl Cellulose/Poly ( Acrylic Acid) Composite Hydrogels with High Mechanical Strength

利用丙烯酸(AA)单体自由基聚合的方法,将羟乙基纤维素(HEC)作为大分子交联剂,引入聚丙烯酸(PAA)水凝胶中,制备了一种具有氢键交联网络结构的羟乙基纤维素/聚丙烯酸(HEC/PAA)复合水凝胶。当HEC质量分数(以水凝胶固含量计)为20.0%、33.3%、42.9%、50.0%和55.5%时,制备的复合水凝胶分别标记为HEC/PAA-1~HEC/PAA-5。采用力学测试和红外光谱(IR)等手段对水凝胶的性能和结构进行了研究。力学测试结果表明:相比于PAA水凝胶较弱的机械性能,复合水凝胶HEC/PAA-2的压缩强度能达到9.52 MPa,对应的压缩断裂应变为91%,压缩断裂能量达到了513.6 kJ/m^3;同时,HEC/PAA水凝胶还表现出了优异的拉伸性能与可恢复性能,HEC/PAA-4的拉伸断裂应力为224.3 k Pa,断裂伸长率为198%,拉伸断裂能量为219.5 kJ/m^3。HEC/PAA-2溶胀150 h时的吸水溶胀率为2.23 g/g。以上结果表明:HEC/PAA复合水凝胶具有的优异力学性能可能源于PAA大分子与HEC大分子之间的氢键作用,它构成了复合水凝胶特殊的网络结构。

A new kind of elastic hydroxyethyl cellulose/poly（ acrylic acid）（ HEC/PAA） composite hydrogels was synthesized via free radical polymerization of acrylic acid（ AA） with hydroxyethyl cellulose that played the role as a cross-linkers via hydrogen bonding interaction. The prepared composite hydrogels were labeled as HEC/PAA-1-HEC/PAA-5,according to the HEC mass fractions（ hydrogel solid content） were 20.0%,33.3%,42.9%,50.0%,55.5%. The properties and structure of these hydrogels were then investigated by the mechanical testing and Fourier-transform infrared spectroscopy（ FT-IR）. The mechanical testing showed that the compressive stress of HEC/PAA-2 composite hydrogels could reach 9. 52 MPa with the strain of about 91%without a break and the compression fracture energy reached 513. 6 kJ/m^3. Meanwhile,HEC/PAA hybrid hydrogels exhibited excellent tensile properties and excellent recoverable performance. The tensile fracture strength of HEC/PAA-4 was 224.3 k Pa,which was associated with 198% elongation at break and the tensile fracture energy of 219.5 kJ/m^3. When HEC/PAA-2 swelled for 150 h,the swelling rate of water was 2. 23 g/g. The mechanical test,FT-IR analysis and swelling properties tests results showed that the hydrogen bonds between the PAA chains and HEC chains formed a special network structure and thus resulted inthe good mechanical properties of composite hydrogels.