PVA/接枝改性淀粉热塑性生物降解材料的制备及应用

以过硫酸铵为引发剂,采用固相法合成了乙酸乙烯酯(VAC)/玉米淀粉接枝共聚物.将其与聚乙烯醇(PVA)、加工助剂在流变仪中共混,制备了PVA/接枝改性淀粉热塑性生物降解材料;分别研究了淀粉接枝共聚物对PVA/淀粉/接枝改性淀粉共混物的加工流动性、耐水性、力学性能和生物降解性能及形态结构的影响.结果表明,PVA/淀粉/接...     

淀粉/PVA可生物降解塑料的研究进展

详细阐述了淀粉/PVA(聚乙烯醇)材料的生物降解机理,从淀粉预处理和PVA预处理这两方面分别对淀粉/PVA可生物降解塑料的热塑性及生物降解性研究进展进行了重点介绍,还对目前国内外淀粉/PVA材料的热塑加工方式进行了综述。     

淀粉/PVA降解塑料耐水性能的研究

实现了淀粉/PVA塑料的热塑性加工,并用正交法研究了PVA、甘油、柠檬酸、水和硼砂用量对淀粉/PVA塑料的耐水性能和力学性能的影响。结果表明:甘油、柠檬酸和水可有效改善淀粉/PVA塑料的加工性能;适量的柠檬酸和甘油可以提高淀粉/PVA塑料的耐水性能;硼砂可以交联淀粉和PVA,并提高淀粉/PVA塑料的耐水性能;增加PVA的用量也可明显提高淀粉塑料的耐水性能。当淀粉与PVA质量比为50/50时,淀粉与PVA的相容性最好。     

玉米淀粉/聚乙烯醇复合发泡材料的制备与表征

以玉米淀粉和聚乙烯醇(PVA)为原料,碳酸氢钠和偶氮二甲酰胺(ADC)为发泡剂,甲醛为交联剂,采用烘培发泡法经缩醛化反应固化成型制备可生物降解复合发泡材料。探究了复合发泡材料的合成条件对材料性能的影响;考察了淀粉与PVA质量比、甲醛用量及发泡剂用量对材料的吸水倍率、回弹率以及密度的影响;测试了PVA醇解度、发泡剂种类对材料耐热性能及泡孔形态的影响;对比了PVA醇解度、不同发泡剂对材料的吸水率及性能的影响;探究了淀粉添加量对材料降解率的影响。结果表明,当m(玉米淀粉)∶m(PVA17-99)=1∶1、甲醛质量分数为12%、发泡剂质量分数为1. 5%时,所得材料的吸水率为3. 84倍,样品密度为0. 330 7 g/cm~3,回弹率为100%,样品呈现空间网状结构,孔泡分布均匀致密; PVA 17-88与PVA 17-99相比吸水率更好; ADC与NaHCO_3相比所制得的材料密度更小,耐热温度偏低;当m(玉米淀粉)∶m(PVA17-99)=1∶1时,材料降解性能较好,失重率达到39%左右。     

淀粉/PVA共混物在缓释肥料中的应用

以淀粉与聚乙烯醇(PVA)的共混材料为基材,用复合肥料(尿素)来制备缓释肥料,通过控制淀粉及PVA在环境中的降解速率以达到控制肥料进入环境和被植物吸收的速率,从而达到既不污染环境,又能够提高肥料利用率的目的。以共混工艺为基础,以甘油和水作为增塑剂,分别研究了增塑剂的种类和加入量、淀粉与PVA的配比对缓释肥料力学性能、流变性能及养分释放性能的影响。利用扫描电镜对其结构进行了表征。结果表明,甘油/水质量比为1/1时加工性能良好,缓释性能随着PVA用量增加累计释放率降低。     

静电纺淀粉/PVA纳米纤维的制备及其交联改性研究

为了提高淀粉纤维的力学性能和水稳定性,使淀粉纤维可以更好地应用于纺织、医药和生物工程等领域,采用静电纺丝法制备淀粉/聚乙烯醇(PVA)纳米纤维,并选择淀粉/PVA质量比为40/60的纳米纤维与戊二醛进行交联。通过扫描电镜、红外光谱(FTIR)仪、差示扫描量热(DSC)分析仪以及万能材料试验机等对纳米纤维的形貌、结构、热性能、力学性能和耐水性等进行了研究。结果表明:随着PVA含量的逐渐升高,淀粉/PVA纳米纤维的直径逐渐变小;FTIR和DSC测试显示淀粉和PVA仅仅是简单的物理共混;两种材料的共混可有效提高纳米纤维的力学性能,当淀粉/PVA质量比为40/60时,淀粉/PVA纳米纤维的力学性能最好;当淀粉/PVA纳米纤维与戊二醛进行交联3~24 h时,淀粉/PVA纳米纤维的接触角由28.31°提高到62.94°,其中交联时间9 h时,接触角为60.18°。     

聚乙烯醇/淀粉/MMT纳米复合材料的制备与性能研究

以蒙脱土（MMT）为增强填料,采用熔融加工的方法制备了聚乙烯醇（PVA）/淀粉/MMT纳米复合材料,通过X射线衍射、差示扫描量热法、扫描电子显微镜、热失重法以及力学性能测试等方法研究了MMT含量对复合材料结构与性能的影响。结果表明,在熔融加工过程中,淀粉、PVA分子破坏了MMT片层结构;MMT提高了复合材料中PVA组分结晶温度,阻碍PVA分子排入晶格,降低了复合材料熔融焓值及结晶度;MMT有效提高了材料的拉伸强度、弹性模量,同时降低了复合材料的吸水速率、平衡吸水率,提高了耐水性能。     

聚乙烯醇/木薯淀粉复合膜的制备与性能

将聚乙烯醇(PVA)与木薯淀粉混合,采用流延法制备PVA/木薯淀粉复合膜,并对其进行了结构表征和性能测试,研究PVA和木薯淀粉不同配比对于复合膜结构和性能的影响。结果表明:PVA和木薯淀粉相容性较好,淀粉的加入提高了PVA的热稳定性,PVA与淀粉的配比对复合膜的综合性能产生重要影响。随着体系中淀粉含量增加,复合膜的拉伸强度和断裂伸长率均先提高后降低,透光率降低,吸水率先降低后升高。当PVA和木薯淀粉配比为70:30时复合膜综合性能最佳,拉伸强度、断裂伸长率、透光率和吸水率分别达到55.65 MPa、337.10%、86.90%和109.52%,优于纯PVA膜。     

淀粉/聚乙烯醇活性包装薄膜及其在食品包装应用中的研究进展

综述了淀粉/聚乙烯醇（PVA）活性包装薄膜及其在食品包装中的研究进展,主要对从不同比例共混、疏水改性、增强改性等方面对淀粉/PVA薄膜的改性研究,从功能特性和活性物质对薄膜性能的影响2个方面对淀粉/PVA活性薄膜研究和薄膜在食品包装中的应用3个方面进行了归纳总结,旨在为以淀粉/PVA为基材的活性包装薄膜研究提供参考。     

淀粉/PVA塑料制备和应用的研究进展

介绍了淀粉/PVA生物降解塑料的制备方法,并分析了溶液流延法、共混挤出和模压成型法的优缺点,阐述了这些技术在淀粉/PVA塑料制备中的进展。针对淀粉塑料的吸水性和生物降解性,对淀粉/PVA塑料的研究方法作了论述,同时对淀粉/PVA塑料的应用也作了介绍,最后展望了淀粉/PVA塑料的发展方向及前景。     

淀粉/PVA生物降解材料的热塑性研究

将聚乙烯醇(PVA)、淀粉、增塑剂在Hakke流变仪中共混制备了热塑性淀粉/PvA材料,研究了2种PVA-PVA1799、PVA1788,2种淀粉-玉米淀粉、木薯淀粉的热塑性情况;比较了甘油、乙二醇、乙酰胺3种增塑剂的增塑效果.结果表明:采用合适的增塑剂与适当的PVA、淀粉组合可以使PVA/淀粉共混体系在高温下热塑成型...     

Plasma treatment for enhancing mechanical and thermal properties of biodegradable PVA/starch blends

Two series of biodegradaable polyvinyl alcohol (PVA)/starch blends, i.e., PVA with/without plasma treatment (PP/P series), were produced by single‐screw extruder. 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 (PPVA) 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/starch blends, the melt flow indices of PPVA/starch blends were improved significantly by 200–300% and their tensile strength also increased two‐to‐three‐fold. Thermogravimetry analysis (TGA) showed that the thermal stability of PPVA/starch (85/300g) blend was better than PVA/starch blend at processing temperature and outperformed than PVA and starch at high temperature. Both the PPVA/starch and PVA/starch blends finished biodegradation within 9–10 weeks in soil burial tests. The esterification reaction of PPVA and glycerol was characterized by FTIR spectroscopic measurement and TGA test. The morphologic evolutions of the blend during biodegradation were investigated carefully by scanning electron microscope (SEM) imaging. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of starch‐based plastic films by electron beam irradiation

Starch‐based plastic films were prepared by the electron beam irradiation of starch and poly(vinyl alcohol) (PVA) in a physical gel state at room temperature. The influence of starch/PVA composition, irradiation dose, and plasticizer (glycerol) on the properties of the plastic films was investigated. The gel fraction of the starch/PVA films increased with both the radiation dose and PVA content in the plastic film and decreased with increasing glycerol concentration. The starch/PVA compatibility was determined by measurement of the thermal properties of the starch/PVA blends with various compositions with differential scanning calorimetry. The swelling of the starch/PVA films increased with increasing PVA content and decreasing irradiation dose. Mechanical studies were carried out, and the tensile strength of the films decreased at high starch ratios in the starch‐based mixture. This was due to the decrease in the degree of crosslinking of starch. Furthermore, when PVA, a biodegradable and flexible‐chain polymer, was incorporated into the starch‐based films, the properties of the films, such as the flexibility (elongation at break), were obviously improved. The tensile strength of the films decreased with increasing glycerol concentration, but elongation at break increased up to a maximum value at a 20% glycerol concentration, and then, it leveled off and decreased slightly. Biodegradation of the starch/PVA plastic films was indicated by weight loss (%) after burial in soil and morphological shape, which was detected by scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 504–513, 2007     

Effect of magnesium chloride hexahydrate on thermal and mechanical properties of starch/PVA films

Starch/poly(vinyl alcohol) (PVA) blend films were prepared from the aqueous solutions containing starch, PVA and magnesium chloride hexahydrate (MgCl₂.6H₂O). The interaction between MgCl₂.6H₂O and starch/PVA was studied by Fourier transform infrared spectroscopy. The plasticising effect of MgCl₂.6H₂O on starch/PVA film was studied by scanning electron microscopy (SEM), X-ray diffraction, thermogravimetric analysis, dynamic mechanical analysis and tensile testing respectively. The water content of starch/PVA films increased with the content of MgCl₂.6H₂O. The absorbed water can act as the plasticiser for starch/PVA film. The crystals of starch and PVA were destroyed, and the crystallinity of starch/PVA film decreased with the plasticising effect of MgCl₂.6H₂O and water. SEM micrographs showed that the compatibility between starch and PVA improved with the addition of MgCl₂.6H₂O. The toughness of starch/PVA film increased with the content of MgCl₂.6H₂O.     

淀粉/PVA在自然土壤环境下的生物降解性能研究

将淀粉与聚乙烯(醇PVA进)行共混,研究了共混物在自然土埋环境中的生物降解过程。结果表明:淀粉的加入可促进PVA的微生物降解速度,使淀粉/PVA试样在120d后分解成小碎片,失重率达到67.8%;对降解不同时间的淀粉/PVA(60/40)片材进行DSC和TG测试发现,降解使材料结晶度和热稳定性提高,说明体系的降解是在无定形区开始的;淀粉/PVA试样的降解过程中,淀粉首先分解,然后是PVA的非晶部分,最后才是PVA的结晶部分。     

SA/PVA可降解复合塑料膜的制备与性能研究

对木薯原淀粉进行乙酰化改性,合成低酯化度的木薯淀粉醋酸酯(SA);经增塑、交联后与聚乙烯醇(PVA)合成可降解的SA/PVA复合塑料膜,重点研究了PVA、甘油、乙二醛的用量及SA的酯化度对复合膜力学性能的影响,并对复合膜性能进行了表征。结果表明:在PVA质量分数为40%,甘油质量分数为14%,乙二醛质量分数为4%时,可以得到力学性能较好的复合塑料膜;与原淀粉/PVA复合膜相比,复合膜致密性提高,玻璃化转变温度降低,结晶度下降,表现出更好的力学性能。     

聚乙烯醇对淀粉/壳聚糖草酸盐复合物及其膜性能的影响

制备了不同含量聚乙烯醇的淀粉/壳聚糖草酸盐复合物及其膜,研究了其溶液的黏度-时间关系、失水率、粒度分布、红外光谱谱图和DSC曲线。结果表明:聚乙烯醇的添加,提高了淀粉/壳聚糖草酸盐复合物的黏度,聚乙烯醇含量越高,其黏度增加的趋势越大;聚乙烯醇含量达到一定程度时,可以提高淀粉/壳聚糖草酸盐复合物失水率;复合物粒径分布范围随聚乙烯醇含量的增加而变窄;红外谱图表明聚乙烯醇与淀粉/壳聚糖草酸盐复合物通过氢键等缔合形成了新结构;DSC表明聚乙烯醇对淀粉/壳聚糖草酸盐复合物膜的热稳定性有一定影响,但仍具有良好的相容性。     

淀粉/OBSH体系发泡的研究

以OBSH为发泡剂,采用单螺杆和双螺杆挤出两种发泡工艺研究了淀粉及淀粉与PVA共混体系的挤出发泡行为,并研究了温度、成核剂滑石粉和发泡助剂尿素对发泡性能的影响。研究发现,发泡工艺对体系发泡倍率有较大影响;随温度升高发泡倍率略有降低;成核剂滑石粉和发泡助剂尿素的加入使淀粉和淀粉/PVA共混体系的发泡倍率都呈先增大后减小的趋势。