【摘要】：通用塑料制品雖然應(yīng)用廣泛,但由于其難以降解、嚴(yán)重污染生態(tài)環(huán)境、且以有限的石化資源為主要原料,因此傳統(tǒng)塑料的發(fā)展和應(yīng)用必將受到越來越多的限制。淀粉來源廣泛,再生周期短,具有綠色環(huán)保的生物降解過程,因而成為生物降解復(fù)合膜的主要原料。但是淀粉基膜或者淀粉/聚乙烯醇(PVA)復(fù)合膜的力學(xué)性能都不盡如人意,膜的耐水性也較差,實(shí)際推廣和應(yīng)用比較難。目前以淀粉及改性淀粉為原料的生物降解膜的研究較多,同時(shí)天然生物聚合物的開發(fā)和應(yīng)用也倍受關(guān)注。為了進(jìn)一步改善淀粉基生物降解膜的力學(xué)性能和耐水性能,使天然可降解聚合物在復(fù)合膜方面得到更好的應(yīng)用,本文以改性淀粉和天然聚合物為主要原料,采用流延工藝制備了一系列新型完全生物降解復(fù)合膜,并對(duì)復(fù)合膜的性能和結(jié)構(gòu)進(jìn)行了測(cè)定和表征。在氧化醋酸酯淀粉(PMS)和聚乙烯醇(PVA)的共混體系中,加入增塑劑山梨醇(SOR)、甘油(GLY)和溶解備用的增強(qiáng)劑羧甲基纖維素(CMC)、海藻酸鈉(SA)及瓊脂(AG),可有效地改善復(fù)合膜的力學(xué)性能和耐水性能,當(dāng)CMC與SA質(zhì)量比為1:1時(shí)膜的拉伸強(qiáng)度(TS)達(dá)20.84 MPa,吸水率(A)124.00%,AG的加入能進(jìn)一步提高膜的耐水性,吸水率降至83.35%。當(dāng)改變?cè)鏊軇┓N類及其含量時(shí),復(fù)合膜的性能也相應(yīng)的發(fā)生變化:在山梨醇為增塑劑時(shí),當(dāng)CMC:SA=1:1時(shí)復(fù)合膜的拉伸強(qiáng)度提高51.5%,斷裂伸長(zhǎng)率(E)提高61.8%,吸水率下降42.9%。而甘油為增塑劑時(shí),復(fù)合膜的拉伸強(qiáng)度小于山梨醇體系,斷裂伸長(zhǎng)率大于山梨醇體系。隨增塑劑用量的增加,復(fù)合膜的拉伸強(qiáng)度降低,斷裂伸長(zhǎng)率增大。在山梨醇、甘油及其復(fù)合增塑劑體系下,CMC、SA和AG的加入均對(duì)復(fù)合膜的性能有改善作用,復(fù)合膜的力學(xué)性能和耐水性的提升尤為明顯。復(fù)合膜的性能雖然受不同因素的影響,但如若在體系中加入少量的天然聚合物作增強(qiáng)劑,復(fù)合膜的性能將進(jìn)一步提升。紅外光譜分析(FTIR)表明淀粉與其它組分之間形成了較強(qiáng)的分子間氫鍵;描電子顯微鏡(SEM)顯示CMC和SA與體系形成了穩(wěn)固的結(jié)構(gòu),少量的AG更能促進(jìn)體系的相容和共混并形成了更牢固的三維網(wǎng)狀結(jié)構(gòu),但過量的AG使復(fù)合膜結(jié)構(gòu)不均勻,相容性變差;X-射線衍射儀(XRD)表明加入瓊脂后復(fù)合膜的結(jié)晶度降低,膜顆粒細(xì)化,相容性較好,柔韌性增強(qiáng);示差掃描量熱分析法(DSC)表明復(fù)合膜具有一定的耐環(huán)境能力。通過正交試驗(yàn),研究并確定了復(fù)合膜最佳性能的工藝條件,在工藝的完善和成本的控制方面提供了一定的參考。
[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.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ317;TB383.2

【共引文獻(xiàn)】

相關(guān)期刊論文 前3條

1 吉海鵬;黃少斌;張瑞峰;;改性淀粉/纖維素共混制膜的力學(xué)性能研究及形態(tài)表征[J];造紙科學(xué)與技術(shù);2013年01期

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相關(guān)博士學(xué)位論文 前1條

1 張建美;地下水硝酸鹽原位生物修復(fù)固相碳源及磷源性能研究[D];中國地質(zhì)大學(xué)(北京);2012年

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本文編號(hào)：2498693