4-羟基丁酸含量对聚 3-羟基丁酸 与 4-羟基丁酸共聚物性能和结构的影响

目的对3-羟基丁酸4-羟基丁酸共聚酯P(3HB-co-4HB)进行酶解测试。方法通过力学性能测试、失重率分析、热失重分析、X-射线衍射分析、扫描电镜等测试和表征手段对样品的物理性能及生物降解情况进行评价。结果 P(3HB-co-4HB)分子中4HB单体(文中均用摩尔分数表示)的引入提高了材料的柔韧性,材料的脆性下降;失重率方面,4种材料的降解速率从高到低依次为P(3HB)P(3HB-co-5%4HB)(3HB-co-10%4HB)P(3HB-co-15%4HB);酶解前期,材料的热稳定性增强,而酶解后期材料的热稳定性逐渐下降;XRD结果表明材料降解过程中结晶度的变化不明显;P(3HB-co-4HB)分子中随着4HB单体含量的增加,材料表面粗糙度降低,酶解后材料表面被侵蚀,降解速率与失重率结果一致。结论 P(3HB-co-4HB)分子中4HB单体的引入显著影响了材料的机械性能,随着4HB含量的增加,材料的失重率越来越大,热稳定性呈现先上升后下降的趋势,材料表面粗糙度逐渐降低,由于酶解过程属于从表面侵蚀开始,因此酶解过程中样品的结晶度变化不大。

Effect of 4-hydroxybutyrate Content on the Property and Structure of Copolyester Poly( 3-hydroxybutyrate-co-4-hydroxybutyrate)

Objective To study the enzymatic degradation processes of P(3HB-co-4HB) . Methods The physical properties and biodegradability were evaluated by mechanical properties test, weight loss, TGA, XRD and SEM. Results The results showed that the presence of 4HB units improved the roughness of the materials, and decreased their brittleness. The degradation rate of 4 materials decreased in the order P(3HB) > P ( 3HB-co-5% 4HB) > ( 3HB-co-10% 4HB) > P ( 3HB-co-15% 4HB) . The thermal stability was slightly improved at the beginning of the degradation and then decreased. The results of XRD showed little difference in crystallinity in the process of enzymatic degradation. With the increase of the fraction of 4HB units,the surface of material became rougher, the surface of material was corroded after enzymatic degradation, and the degradation rate was consistent with the results of weight loss rate. Conclusion The presence of 4HB units remarkably influenced the mechanical properties of the materials, with the increase of the fraction of 4HB units, the weight loss increased, the thermal stability first increased and then decreased, the surface of materials got rougher, and the crystallinity had no change for the surface erosion in the process of enzymatic degradation.