天然聚合物可降解复合膜的制备及性能研究
发布时间：2019-06-13 17:36
【摘要】：通用塑料制品虽然应用广泛,但由于其难以降解、严重污染生态环境、且以有限的石化资源为主要原料,因此传统塑料的发展和应用必将受到越来越多的限制。淀粉来源广泛,再生周期短,具有绿色环保的生物降解过程,因而成为生物降解复合膜的主要原料。但是淀粉基膜或者淀粉/聚乙烯醇(PVA)复合膜的力学性能都不尽如人意,膜的耐水性也较差,实际推广和应用比较难。目前以淀粉及改性淀粉为原料的生物降解膜的研究较多,同时天然生物聚合物的开发和应用也倍受关注。为了进一步改善淀粉基生物降解膜的力学性能和耐水性能,使天然可降解聚合物在复合膜方面得到更好的应用,本文以改性淀粉和天然聚合物为主要原料,采用流延工艺制备了一系列新型完全生物降解复合膜,并对复合膜的性能和结构进行了测定和表征。在氧化醋酸酯淀粉(PMS)和聚乙烯醇(PVA)的共混体系中,加入增塑剂山梨醇(SOR)、甘油(GLY)和溶解备用的增强剂羧甲基纤维素(CMC)、海藻酸钠(SA)及琼脂(AG),可有效地改善复合膜的力学性能和耐水性能,当CMC与SA质量比为1:1时膜的拉伸强度(TS)达20.84 MPa,吸水率(A)124.00%,AG的加入能进一步提高膜的耐水性,吸水率降至83.35%。当改变增塑剂种类及其含量时,复合膜的性能也相应的发生变化:在山梨醇为增塑剂时,当CMC:SA=1:1时复合膜的拉伸强度提高51.5%,断裂伸长率(E)提高61.8%,吸水率下降42.9%。而甘油为增塑剂时,复合膜的拉伸强度小于山梨醇体系,断裂伸长率大于山梨醇体系。随增塑剂用量的增加,复合膜的拉伸强度降低,断裂伸长率增大。在山梨醇、甘油及其复合增塑剂体系下,CMC、SA和AG的加入均对复合膜的性能有改善作用,复合膜的力学性能和耐水性的提升尤为明显。复合膜的性能虽然受不同因素的影响,但如若在体系中加入少量的天然聚合物作增强剂,复合膜的性能将进一步提升。红外光谱分析(FTIR)表明淀粉与其它组分之间形成了较强的分子间氢键;描电子显微镜(SEM)显示CMC和SA与体系形成了稳固的结构,少量的AG更能促进体系的相容和共混并形成了更牢固的三维网状结构,但过量的AG使复合膜结构不均匀,相容性变差;X-射线衍射仪(XRD)表明加入琼脂后复合膜的结晶度降低,膜颗粒细化,相容性较好,柔韧性增强;示差扫描量热分析法(DSC)表明复合膜具有一定的耐环境能力。通过正交试验,研究并确定了复合膜最佳性能的工艺条件,在工艺的完善和成本的控制方面提供了一定的参考。
[Abstract]:Although the general plastic products are widely used, because they are difficult to degrade, seriously pollute the ecological environment, and take the limited petrochemical resources as the main raw materials, the development and application of traditional plastics will be restricted more and more. Starch has a wide range of sources, short regeneration cycle and green and environmentally friendly biodegradation process, so it has become the main raw material of biodegradable composite membrane. However, the mechanical properties of starch based membrane or starch / polyvinyl alcohol (PVA) composite membrane are not satisfactory, and the water resistance of the membrane is also poor, so it is difficult to popularize and apply in practice. At present, there are many studies on biodegradable membranes based on starch and modified starch. At the same time, the development and application of natural biopolymers have also attracted much attention. In order to further improve the mechanical properties and water resistance of starch based biodegradable membranes and make natural degradable polymers better used in composite membranes, a series of new completely biodegradable composite membranes were prepared by casting process with modified starch and natural polymers as main raw materials, and the properties and structure of the composite membranes were measured and characterized. In the blend system of oxidized acetate starch (PMS) and polyvinyl alcohol (PVA), the mechanical properties and water resistance of the composite membrane could be effectively improved by adding sorbitol (SOR), glycerol (GLY) and dissolved reinforcer Carbomethyl cellulose (CMC), sodium alginate (SA) and Agar (AG),. When the mass ratio of CMC to SA was 1: 1, the tensile strength of the film reached 20.84 MPa,. The water absorption rate of (A) is 124.00%. The addition of AG can further improve the water resistance of the film, and the water absorption rate can be reduced to 83.35%. When the type and content of plasticizer were changed, the properties of the composite film also changed accordingly: when sorbitol was used as plasticizer, the tensile strength of the composite film increased by 51.5%, the (E) at break increased by 61.8%, and the water absorption decreased by 42.9% when sorbitol was used as plasticizer. When glycerol was used as plasticizer, the tensile strength of the composite film was lower than that of sorbitol system, and the elongation at break was higher than that of sorbitol system. With the increase of the amount of plasticizer, the tensile strength of the composite film decreased and the elongation at break increased. In the system of sorbitol, glycerol and their composite plasticizers, the addition of CMC,SA and AG can improve the properties of the composite membrane, especially the mechanical properties and water resistance of the composite membrane. Although the properties of the composite membrane are affected by different factors, if a small amount of natural polymer is added to the system as reinforcer, the performance of the composite film will be further improved. Infrared spectrum analysis (FTIR) showed that there was a strong intermolecular hydrogen bond between starch and other components, and electron microscope (SEM) showed that CMC and SA formed a stable structure with the system, a small amount of AG could promote the compatibility and blending of the system and form a stronger three-dimensional network structure, but excessive AG made the structure of the composite membrane uneven and the compatibility became worse. X-ray diffractometer (XRD) showed that the crystallization of the composite film decreased, the particles of the composite film were refined, the compatibility of the film was good and the flexibility was enhanced after adding Agar. (DSC) showed that the composite film had certain environmental resistance. Through orthogonal test, the technological conditions of the optimum performance of the composite membrane were studied and determined, which provided a certain reference for the improvement of the process and the control of the cost.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ317;TB383.2
本文编号：2498693
[Abstract]:Although the general plastic products are widely used, because they are difficult to degrade, seriously pollute the ecological environment, and take the limited petrochemical resources as the main raw materials, the development and application of traditional plastics will be restricted more and more. Starch has a wide range of sources, short regeneration cycle and green and environmentally friendly biodegradation process, so it has become the main raw material of biodegradable composite membrane. However, the mechanical properties of starch based membrane or starch / polyvinyl alcohol (PVA) composite membrane are not satisfactory, and the water resistance of the membrane is also poor, so it is difficult to popularize and apply in practice. At present, there are many studies on biodegradable membranes based on starch and modified starch. At the same time, the development and application of natural biopolymers have also attracted much attention. In order to further improve the mechanical properties and water resistance of starch based biodegradable membranes and make natural degradable polymers better used in composite membranes, a series of new completely biodegradable composite membranes were prepared by casting process with modified starch and natural polymers as main raw materials, and the properties and structure of the composite membranes were measured and characterized. In the blend system of oxidized acetate starch (PMS) and polyvinyl alcohol (PVA), the mechanical properties and water resistance of the composite membrane could be effectively improved by adding sorbitol (SOR), glycerol (GLY) and dissolved reinforcer Carbomethyl cellulose (CMC), sodium alginate (SA) and Agar (AG),. When the mass ratio of CMC to SA was 1: 1, the tensile strength of the film reached 20.84 MPa,. The water absorption rate of (A) is 124.00%. The addition of AG can further improve the water resistance of the film, and the water absorption rate can be reduced to 83.35%. When the type and content of plasticizer were changed, the properties of the composite film also changed accordingly: when sorbitol was used as plasticizer, the tensile strength of the composite film increased by 51.5%, the (E) at break increased by 61.8%, and the water absorption decreased by 42.9% when sorbitol was used as plasticizer. When glycerol was used as plasticizer, the tensile strength of the composite film was lower than that of sorbitol system, and the elongation at break was higher than that of sorbitol system. With the increase of the amount of plasticizer, the tensile strength of the composite film decreased and the elongation at break increased. In the system of sorbitol, glycerol and their composite plasticizers, the addition of CMC,SA and AG can improve the properties of the composite membrane, especially the mechanical properties and water resistance of the composite membrane. Although the properties of the composite membrane are affected by different factors, if a small amount of natural polymer is added to the system as reinforcer, the performance of the composite film will be further improved. Infrared spectrum analysis (FTIR) showed that there was a strong intermolecular hydrogen bond between starch and other components, and electron microscope (SEM) showed that CMC and SA formed a stable structure with the system, a small amount of AG could promote the compatibility and blending of the system and form a stronger three-dimensional network structure, but excessive AG made the structure of the composite membrane uneven and the compatibility became worse. X-ray diffractometer (XRD) showed that the crystallization of the composite film decreased, the particles of the composite film were refined, the compatibility of the film was good and the flexibility was enhanced after adding Agar. (DSC) showed that the composite film had certain environmental resistance. Through orthogonal test, the technological conditions of the optimum performance of the composite membrane were studied and determined, which provided a certain reference for the improvement of the process and the control of the cost.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ317;TB383.2
【共引文献】
相关期刊论文 前3条
1 吉海鹏;黄少斌;张瑞峰;;改性淀粉/纤维素共混制膜的力学性能研究及形态表征[J];造纸科学与技术;2013年01期
2 张佳;王瑞;徐磊;苏阳;;强剪切作用对全淀粉塑料结构和性能的影响[J];中国塑料;2014年08期
3 杜敏;姜桥;李新平;张丹;;纳米晶体纤维素对淀粉基复合薄膜性能的影响[J];陕西科技大学学报(自然科学版);2015年04期
相关博士学位论文 前1条
1 张建美;地下水硝酸盐原位生物修复固相碳源及磷源性能研究[D];中国地质大学(北京);2012年
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