竹纤维增强P34HB复合材料及P34HB热稳定性的研究
发布时间：2018-09-18 17:17
【摘要】：聚3-羟基丁酸酯4-羟基丁酸酯（P34HB）作为最新一代的PHA生物基高分子，不仅具有生物降解性和生物来源，还拥有良好的综合性能，已应用在生物医药、包装和农业等领域。但是P34HB在结晶性、力学性能和热稳定性等方面存在不足，如何克服这些缺陷是P34HB进一步发展和推广的必经之路。 本论文中，针对P34HB力学性能的不足而引入了天然竹纤维（BF），采用了碱处理、马来酸酐改性和硅烷偶联剂改性三种方法对BF进行改性。结果表明，当BF在5wt%的NaOH溶液中处理8h，添加量为10phr时，制备的P34HB/竹纤维复合材料的力学性能最佳，拉伸强度和弯曲强度分别较纯P34HB提高了58.63%和46.22%。分析表明，BF经碱处理后，直径减小、长径比增大、纤维素含量大幅提高，有利于提高纤维与基体的相容性。竹纤维的引入可以在基体中起到成核剂的作用，提高P34HB的结晶性能，对P34HB的热稳定性有一定的改善，但当竹纤维含量增大时，复合材料热稳定性能下降。 另一方面，本论文研究了填料种类对P34HB热稳定性能的影响。研究发现，，用具有自有知识产权的固相改性法改性MMT，得到含有酯基EMMT能够大幅提高了P34HB的热稳定性，当EMMT的含量为5phr时，热降解温度从纯P34HB的231.6℃提高到270.4℃，提高了近40℃，维卡软化点也从原来的52.3℃提高至58.2℃。TGA-IR测试表明， EMMT的引入并没有改变其降解机理，但是复合材料的比热和导热系数均得到增大，有利于P34HB热稳定性的提高。DSC测试表明，EMMT对P34HB具有成核作用，Tc从纯P34HB的70.8℃提高到93.2℃，提高了22.4℃。TEM和XRD分析表明，P34HB基体能够进一步插到EMMT层间，EMMT在基体中分散性较好，蒙脱土的分散尺度在20nm-70nm之间，达到纳米级别。结合材料的力学性能，当EMMT的含量为5phr时，P34HB/EMMT纳米复合材料综合性能最佳。 降解分析表明， P34HB、P34HB/ATBF(碱处理后的BF)及P34HB/EMMT材料在pH=1.3的磷酸溶液中很稳定，降解缓慢，但在pH=13的NaOH溶液中降解速率很快。酸降解后的试样结晶性和热稳定性变化不大，而因为P34HB分子链上的酯基对碱敏感，在碱性条件下容易发生分子链断裂，所以试样在碱降解后结晶性能、热稳定性均下降。
[Abstract]:Poly (3-hydroxybutyrate) 4-hydroxybutyrate (P34HB), as the latest generation of PHA biomaterials, not only has biodegradability and biodegradability, but also has good comprehensive properties. It has been used in biomedicine, packaging and agriculture. However, there are some shortcomings in crystallization, mechanical properties and thermal stability of P34HB. How to overcome these defects is the only way to further develop and popularize P34HB. In this paper, the natural bamboo fiber (BF), was modified by alkali treatment, maleic anhydride modification and silane coupling agent modification to improve the mechanical properties of P34HB. The results showed that when BF was treated in 5 wt% NaOH solution for 8 h and the amount of 10phr was added, the mechanical properties of the P34HB/ bamboo fiber composites were the best. The tensile strength and bending strength of the P34HB/ bamboo fiber composites were increased by 58.63% and 46.2222%, respectively, compared with the pure P34HB. The analysis shows that after alkali treatment, the diameter of BF decreases, the aspect ratio increases, and the content of cellulose increases significantly, which is beneficial to improve the compatibility between fiber and matrix. The introduction of bamboo fiber can play the role of nucleating agent in the matrix, improve the crystallization property of P34HB and improve the thermal stability of P34HB to some extent, but when the content of bamboo fiber increases, the thermal stability of the composite decreases. On the other hand, the effect of filler type on the thermal stability of P34HB was studied. It is found that the thermal stability of P34HB can be greatly improved by modifying MMT, with solid phase modification with its own intellectual property rights. When the content of EMMT is 5phr, the thermal degradation temperature is raised from 231.6 鈩
本文编号：2248590
[Abstract]:Poly (3-hydroxybutyrate) 4-hydroxybutyrate (P34HB), as the latest generation of PHA biomaterials, not only has biodegradability and biodegradability, but also has good comprehensive properties. It has been used in biomedicine, packaging and agriculture. However, there are some shortcomings in crystallization, mechanical properties and thermal stability of P34HB. How to overcome these defects is the only way to further develop and popularize P34HB. In this paper, the natural bamboo fiber (BF), was modified by alkali treatment, maleic anhydride modification and silane coupling agent modification to improve the mechanical properties of P34HB. The results showed that when BF was treated in 5 wt% NaOH solution for 8 h and the amount of 10phr was added, the mechanical properties of the P34HB/ bamboo fiber composites were the best. The tensile strength and bending strength of the P34HB/ bamboo fiber composites were increased by 58.63% and 46.2222%, respectively, compared with the pure P34HB. The analysis shows that after alkali treatment, the diameter of BF decreases, the aspect ratio increases, and the content of cellulose increases significantly, which is beneficial to improve the compatibility between fiber and matrix. The introduction of bamboo fiber can play the role of nucleating agent in the matrix, improve the crystallization property of P34HB and improve the thermal stability of P34HB to some extent, but when the content of bamboo fiber increases, the thermal stability of the composite decreases. On the other hand, the effect of filler type on the thermal stability of P34HB was studied. It is found that the thermal stability of P34HB can be greatly improved by modifying MMT, with solid phase modification with its own intellectual property rights. When the content of EMMT is 5phr, the thermal degradation temperature is raised from 231.6 鈩
本文编号：2248590
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