聚（3-羟基丁酸酯-co-4-羟基丁酸酯）基复合材料的制备与性能研究
发布时间：2018-08-20 12:39
【摘要】：聚羟基脂肪酸酯(PHA)是近年来迅速发展起来的一类生物高分子材料,由于PHA材料具有良好的生物相容性、生物可降解性和热加工性能,被认为是最具有竞争力可替代部分传统石油基塑料的一种新型材料。聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3,4)HB]是PHA的典型代表,自身存在着结晶速度慢、加工温度范围窄、断裂伸长率低以及易燃等缺陷。本论文在对PHA基复合材料研究进展进行文献调研的基础上,分别利用纳米二氧化硅(SiO2)和聚氨酯弹性体(PU)作为填料,制备P(3,4)HB基复合材料。通过对其力学性能、结晶性能和热性能的研究,探索制备可生物降解聚酯增强增韧改性的新途径。论文主要研究内容如下:首先,采用改进的St?ber法,制备粒径可控的200~400nm单分散SiO2微球,并利用硅烷偶联剂KH-550对其进行表面改性,以提高其疏水性。采用熔融共混法将改性后的SiO2与P(3,4)HB进行复合,制备P(3,4)HB/SiO2复合材料,并对其力学性能和结晶性能进行研究。结果表明,添加少量的SiO2后,P(3,4)HB/SiO2复合材料的拉伸强度和模量明显提高,且当SiO2含量为3 wt%时效果最为显著,然而,材料的断裂伸长率略有下降。差示扫描量热(DSC)和偏光显微(POM)分析结果显示,SiO2能够使P(3,4)HB冷结晶温度(Tcc)降低、晶粒细化,表明SiO2对P(3,4)HB的结晶有促进作用。其次,采用一步法合成了硬段含量为45%的聚酯型PU,进而采用溶液共混法制备了P(3,4)HB/PU复合材料,并对其微观结构、力学性能、结晶性能和热性能进行了测试和分析。研究结果表明,PU能够以纳米尺度分散在P(3,4)HB基体中。随着PU含量的增加,P(3,4)HB/PU复合材料的断裂伸长率逐渐增大,而屈服强度和弹性模量均有所降低。扫描电镜(SEM)结果显示,与纯基体P(3,4)HB相比,复合材料的断裂特征从典型的脆性断裂转变为韧性断裂。此外,PU的添加能提高复合材料的热稳定性、减缓复合材料的生物降解速率,但其球晶尺寸变大、Tcc提高,表明PU对其结晶性能有一定的阻碍作用。最后,合成了三种不同硬段含量的聚酯型PU(包括35%PU,45%PU,55%PU),并通过溶液共混法制备P(3,4)HB/PU复合材料,对比研究其增韧效果。研究结果表明,三种不同硬段含量的PU对P(3,4)HB基体均有明显的增韧作用,且添加量越大增韧效果越显著。相比较而言,55%PU的增韧效果最为突出,P(3,4)HB-55%PU复合材料的断裂强度显著提高,出现了应力应变曲线持续增加的现象;而35%PU的增韧效果较差,P(3,4)HB-35%PU复合材料的屈服强度下降的最多。三种不同硬段含量的PU均使得P(3,4)HB/PU复合材料的热稳定性提高,但结晶性能均有一定的下降。
[Abstract]:Polyhydroxyl fatty acid ester (PHA) is a kind of biomaterials developed rapidly in recent years. Because of its good biocompatibility, biodegradability and hot processing properties, PHA materials have been widely used in many fields. It is considered to be the most competitive alternative to some of the traditional petroleum-based plastics a new material. Poly (3-hydroxybutyrate -co-4hydroxybutyrate) [P (3Hb) HB] is a typical representative of PHA. It has some defects such as slow crystallization rate, narrow processing temperature, low elongation at break and flammability. In this paper, based on the research progress of PHA matrix composites, P _ (3O _ 4) HB matrix composites were prepared by using nano-silica (SiO2) and polyurethane elastomer (PU) as fillers, respectively. Through the study of mechanical properties, crystallization properties and thermal properties, a new way to prepare biodegradable polyester reinforced and toughened modification was explored. The main contents of this paper are as follows: firstly, the 200~400nm monodisperse SiO2 microspheres with controllable particle size were prepared by modified St?ber method, and the surface of SiO2 microspheres was modified by silane coupling agent KH-550 to improve its hydrophobicity. The modified SiO2 and P _ (3O _ 4) HB composites were prepared by melt blending method. The mechanical properties and crystallization properties of P _ (3O _ 4) HB/SiO2 composites were studied. The results showed that the tensile strength and modulus of P _ (3N _ 4) HB/SiO2 composites increased obviously after adding a small amount of SiO2, and the tensile strength and modulus of P _ (3) O _ (4) HB/SiO2 composites were the most obvious when the content of SiO2 was 3 wt%. However, the elongation at break of the composites decreased slightly. The results of differential scanning calorimetry (DSC) and polarizing microscopy (POM) show that SiO2 can decrease the cold crystallization temperature (Tcc) of P _ (3O _ 4) HB and refine the grain size, indicating that SiO2 can promote the crystallization of P _ (3O _ 4) HB. Secondly, a 45% hard segment polyester-type HB/PU composite was synthesized by one-step method, and then P _ (3O _ 4) HB/PU composites were prepared by solution blending method. The microstructure, mechanical properties, crystallization properties and thermal properties of the composites were tested and analyzed. The results show that pu can be dispersed in P _ (3O _ 4) HB matrix on nanometer scale. With the increase of pu content, the elongation at break of P _ (3O _ 4) HB/PU composites increases gradually, while the yield strength and elastic modulus decrease. The results of scanning electron microscopy (SEM) showed that the fracture characteristics of the composites changed from typical brittle fracture to ductile fracture compared with pure matrix P _ (3N _ 4) HB. In addition, the addition of pu can improve the thermal stability of the composites and slow down the biodegradation rate of the composites, but the spherulite size of the composites increases with the increase of TCC, indicating that pu has a certain blocking effect on the crystallization properties of the composites. Finally, three kinds of polyester pu with different hard segment contents (including 35PU45PU55PU) were synthesized, and P (3N 4) HB/PU composites were prepared by solution blending method. The toughening effects of the composites were compared and studied. The results show that three kinds of pu with different hard segment content have obvious toughening effect on P _ (3O _ 4) HB matrix, and the more the content of pu is, the more obvious the toughening effect is. By comparison, the toughening effect of pu is the most prominent, the fracture strength of P _ (3O _ 4) HB-55%PU composites increases significantly, and the stress-strain curve increases continuously, while the yield strength of P _ (3O _ 4) HB-35%PU composites decreases the most when the toughening effect of 35%PU is worse than that of P _ (3N _ 4) HB-35%PU composites. The thermal stability of P _ (3) O _ (4) HB/PU composites was improved by three kinds of pu with different hard segment content, but the crystallization properties of P _ (3) O _ (4) HB/PU composites decreased to some extent.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ317;TB33
本文编号：2193635
[Abstract]:Polyhydroxyl fatty acid ester (PHA) is a kind of biomaterials developed rapidly in recent years. Because of its good biocompatibility, biodegradability and hot processing properties, PHA materials have been widely used in many fields. It is considered to be the most competitive alternative to some of the traditional petroleum-based plastics a new material. Poly (3-hydroxybutyrate -co-4hydroxybutyrate) [P (3Hb) HB] is a typical representative of PHA. It has some defects such as slow crystallization rate, narrow processing temperature, low elongation at break and flammability. In this paper, based on the research progress of PHA matrix composites, P _ (3O _ 4) HB matrix composites were prepared by using nano-silica (SiO2) and polyurethane elastomer (PU) as fillers, respectively. Through the study of mechanical properties, crystallization properties and thermal properties, a new way to prepare biodegradable polyester reinforced and toughened modification was explored. The main contents of this paper are as follows: firstly, the 200~400nm monodisperse SiO2 microspheres with controllable particle size were prepared by modified St?ber method, and the surface of SiO2 microspheres was modified by silane coupling agent KH-550 to improve its hydrophobicity. The modified SiO2 and P _ (3O _ 4) HB composites were prepared by melt blending method. The mechanical properties and crystallization properties of P _ (3O _ 4) HB/SiO2 composites were studied. The results showed that the tensile strength and modulus of P _ (3N _ 4) HB/SiO2 composites increased obviously after adding a small amount of SiO2, and the tensile strength and modulus of P _ (3) O _ (4) HB/SiO2 composites were the most obvious when the content of SiO2 was 3 wt%. However, the elongation at break of the composites decreased slightly. The results of differential scanning calorimetry (DSC) and polarizing microscopy (POM) show that SiO2 can decrease the cold crystallization temperature (Tcc) of P _ (3O _ 4) HB and refine the grain size, indicating that SiO2 can promote the crystallization of P _ (3O _ 4) HB. Secondly, a 45% hard segment polyester-type HB/PU composite was synthesized by one-step method, and then P _ (3O _ 4) HB/PU composites were prepared by solution blending method. The microstructure, mechanical properties, crystallization properties and thermal properties of the composites were tested and analyzed. The results show that pu can be dispersed in P _ (3O _ 4) HB matrix on nanometer scale. With the increase of pu content, the elongation at break of P _ (3O _ 4) HB/PU composites increases gradually, while the yield strength and elastic modulus decrease. The results of scanning electron microscopy (SEM) showed that the fracture characteristics of the composites changed from typical brittle fracture to ductile fracture compared with pure matrix P _ (3N _ 4) HB. In addition, the addition of pu can improve the thermal stability of the composites and slow down the biodegradation rate of the composites, but the spherulite size of the composites increases with the increase of TCC, indicating that pu has a certain blocking effect on the crystallization properties of the composites. Finally, three kinds of polyester pu with different hard segment contents (including 35PU45PU55PU) were synthesized, and P (3N 4) HB/PU composites were prepared by solution blending method. The toughening effects of the composites were compared and studied. The results show that three kinds of pu with different hard segment content have obvious toughening effect on P _ (3O _ 4) HB matrix, and the more the content of pu is, the more obvious the toughening effect is. By comparison, the toughening effect of pu is the most prominent, the fracture strength of P _ (3O _ 4) HB-55%PU composites increases significantly, and the stress-strain curve increases continuously, while the yield strength of P _ (3O _ 4) HB-35%PU composites decreases the most when the toughening effect of 35%PU is worse than that of P _ (3N _ 4) HB-35%PU composites. The thermal stability of P _ (3) O _ (4) HB/PU composites was improved by three kinds of pu with different hard segment content, but the crystallization properties of P _ (3) O _ (4) HB/PU composites decreased to some extent.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ317;TB33
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