生物可分解性聚乙烯醇/樹薯澱粉混煉物之特性研究

The Investigation of Biodegradable PVA/ Tapioca Starch Blend and its Properties

楊森源(Sung-Yeng Yang)

指導教授 ： 黃繼遠

大同大學/工程學院/材料工程學系所/博士(2008年)

摘要

本研究中，聚乙烯醇、甘油、水、樹薯澱粉與所有添加的酸均利用單螺桿押出機混煉而得到各種不同的聚乙烯醇/樹薯澱粉的生物分解材料。第一部分主要在探討聚乙烯醇的最佳比例與聚乙烯醇經電漿處理後顯現在拉伸性質、熱學性質、加工性質、與生物分解性質上的效果，聚乙烯醇經過電漿處理後可以與甘油生成酯化物，這點可以經由FTIR的圖譜得到驗證，此酯化物可以同時強化混煉物的機械性質並且提高聚乙烯醇與澱粉的相容性。經過電漿處理後的混煉物比起未處理前，其熔融指數與拉伸強度均提高2至3倍，且熔融指數與拉伸強度可以高達4.42 g/10 min 與6.24 MPa。第二部分在探討酸解效果與電漿處理對混煉物在加工性質與機械性質上的提升，研究證實聚乙烯醇/樹薯澱粉的混煉物加入馬來酸酐後，其熔融指數由2.3g/10min 提高至 32.7 g/10min，再經電漿處理則可以更加提升到130 g/10min，另外混煉物利用馬來酸酐與檸檬酸的改質，拉伸強度可以從3.48 MPa 提高到 6.21 MPa。第三部份探討樹薯澱粉與混煉物在（1）一般堆肥，（2）加入Rhizopus arrhizus 的一般堆肥與（3）堆肥滅菌後加入Rhizopus arrhizus等三種狀態下實施生物分解性測試。兩者完全分解的時間長度都是（3）＞（2）＞（1），證實Rhizopus arrhizus對澱粉的分解確實有效，同時也使用電子顯微鏡觀察Rhizopus arrhizus在澱粉中的繁殖模式。
本研究也證實熱壓後的試片，不論酸解處理或電漿處理與否，聚乙烯醇/樹薯澱粉的混煉物在含水量25至45％的堆肥中從事生物分解測試，均在16週之內便完全被堆肥土中的微生物分解。具有最佳機械與加工性能的聚乙烯醇/樹薯澱粉/甘油混煉物之組成比例為85/300/60克。

關鍵字

聚乙烯醇 ； 澱粉

並列摘要

In this study, PVA, glycerol, water, tapioca starch and additives were prepared by single-screw extruder to produce PVA/starch biodegradable materials. First, the influences of plasma pretreatment and PVA content on the tensile properties, thermal behaviors, melt flow index, and biodegradability of blends were investigated. PVA pretreated by plasma and reacted with glycerol was found not only to mechanically strengthen the PPVA/starch blend but also to improve the compatibility of PPVA and starch. Compared with PVA/tapioca starch blends, the melt flow indices of PPVA/tapioca starch blends were improved significantly by 200 to 300% and their tensile strength also increased two-to-three-fold. The esterification reaction of PPVA and glycerol was characterized by FTIR spectroscopic measurement and TGA test and the morphologic evolutions of the blend during biodegradation were investigated carefully by Scanning electron microscope (SEM) imaging. Second, maleic anhydride (MA), and citric acid (CA) used as the processing additive and plasma treatment to improve the processing ability and mechanical strength of biodegradable PVA/tapioca starch blends. The melt flow index (MFI) of blend was increased from 2.3g/10min to 32.7 g/10min by adding MA and to 130 g/10min by adding MA and plasma treatment. The tensile strength of blend increased from 3.48 to 6.21 MPa by adding MA and CA, while it increased to 6.26 MPa by plasma treatment. Third, tapioca starch and PVA/tapioca starch blend films were buried in soil for sixteen weeks in order to study the different biodegradation rates among these two materials. Burial tests were performance in three different soil conditions: (a) general compost, (b) adding Rhizopus arrhizus fungus in compost and (c) adding Rhizopus arrhizus fungus in compost after sterilization. The complete biodegradation time of PVA/starch blend were in the order as (c) test (10 weeks burial time) < (b) test (12 weeks) < (a) test (16 weeks). The biodegradation of starch has the same tendency among these burial soil conditions, but degradation time was shortening to 6, 8 and 10 weeks. Some morphological aspects of the growth of Rhizopus arrhizus on tapioca starch were studied by scanning electron microscopy (SEM).
In the investigation of this study, all the samples of PVA/tapioca starch blends, whether adding acid modification or plasma treatment or not and at least 25% water content in the compost, are completely biodegraded in compost within sixteen weeks. The optimal composition of the blend (PVA/tapioca starch/glycerol) having outstanding mechanical and processing properties is 85/300/60g.

並列關鍵字

Starch ； PVA

參考文獻

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