海藻酸钠/羧甲基淀粉共混膜

用溶液共混法成功制备出海藻酸钠／羧甲基淀粉共混膜，IR、XRD、SEM结构表征以及力学性能、吸水性和水蒸汽透过率测定结果表明：共混膜中海藻酸钠和羧甲基淀粉间存在强烈的分子间氢键等相互作用及良好的相容性；随羧甲基淀粉含量的增加，共混膜的吸水率显著降低；当羧甲基淀粉含量(wCMS)=0．20时，共混膜的抗张强度和断裂伸长率分别为53．1MPa和5．3％，比海藻酸钠膜分别提高了97．4％和60．6％，水蒸汽透过率达最小值，是一种具有潜在应用前景的可食性包装膜材料。     

水辅助加工法制备聚丙撑碳酸酯/淀粉共混物

分别采用普通熔融共混法和水辅助加工法,制备了具有不同共混形态的聚丙撑碳酸酯(PPC)/淀粉共混物,并研究了淀粉分散形态对共混物的玻璃化转变温度(Tg)、流变以及力学性能的影响。研究结果表明,采用普通熔融共混法时,淀粉未发生糊化,并以原颗粒状分散于基体中;而采用水辅助加工法时,淀粉发生糊化,并在挤出过程中原位形成纤维结构。当淀粉以纤维形式分散于PPC基体中时,其与PPC间的界面接触面积显著增加,二者的相互作用增强,PPC/淀粉共混物的Tg、储能模量以及复合黏度显著提高。力学性能测试结果表明,当淀粉质量分数为30%,采用水辅助加工法制备的PPC/淀粉共混物的拉伸模量相比于纯PPC提高了67.7%。     

聚乙烯醇－淀粉共混溶液流变特性研究

聚乙烯醇－淀粉共混溶液流变特性研究邱威扬，邱贤华，喻继文，吴素果（江西科学院应用化学研究所南昌３３００２９）关键词聚乙烯醇，淀粉，共混，流变特性淀粉塑料是目前国内外研究的热点，各国已宣布研制成功多种淀粉塑料．据报道８０年代末以来，生产量以７５％的年增...     

聚乙烯醇－淀粉共混溶液流变特性研究

聚乙烯醇－淀粉共混溶液流变特性研究邱威扬，邱贤华，喻继文，吴素果（江西科学院应用化学研究所南昌３３００２９）关键词聚乙烯醇，淀粉，共混，流变特性淀粉塑料是目前国内外研究的热点，各国已宣布研制成功多种淀粉塑料．据报道８０年代末以来，生产量以７５％的年增...     

乙烯-辛烯共聚物/淀粉共混体系的非等温结晶动力学(英文)

通过差示扫描量热仪(DSC)研究了乙烯-辛烯共聚物/淀粉共混体系的非等温结晶动力学,用Jeziorny和Ozawa方程描述了结晶动力学过程.共混物的结晶温度和结晶焓强烈依赖于淀粉含量和冷却速率.结果表明,随着冷却速率的增加,每个试样的结晶放热曲线均变宽,并向低温区移动.当温度一定高时,所有试样均具有较快的结晶速率. Jeniorzy方程可以较好地描述POE/淀粉共混物的非等温结晶模式,而Ozawa方程对于POE/淀粉共混体系不太适合.     

高速搅拌对淀粉/聚乙烯醇共混物溶液成膜性能的影响

淀粉与聚乙烯醇（ＰＶＡ）溶液在高速搅拌下共混,可大大改善淀粉／ＰＶＡ共混薄膜的力学性能、透明性与耐水性,对其生物降解性有明显的影响．淀粉／ＰＶＡ共混体系在高速搅拌前后的光谱分析、显微观察、分子量及流变性能的测定表明,这些变化起因于高速搅拌增加了淀粉中直链淀粉的含量,同时提高了淀粉与ＰＶＡ共混溶液的稳定性,改善了淀粉／ＰＶＡ共混物薄膜的使用性能．     

淀粉接枝丙烯酸乙酯及其增容性

研究了在挤出机中采用高温和剪切力的作用直接引发淀粉与丙烯酸乙酯的接枝共聚合反应．讨论了反应条件对接枝反应的影响，研究了接枝物在淀粉与聚乙烯共混物中的增容作用．实验结果表明，高温和剪切力可以引发淀粉与丙烯酸乙酯的接枝共聚合反应．接枝物作为增容剂，可以明显地改善淀粉与聚乙烯共混物的力学性能和流变性能．     

改性淀粉/聚乳酸共混体系增容方法的研究

研究了聚乳酸和改性淀粉共混挤出前的固相酯化反应对共混体系的增容作用。比较挤出样条经二氯甲烷抽提后剩余物的固体13C-NMR光谱谱图,发现未经酯化反应时剩余物为淀粉,经酯化反应后剩余物的固体13C-NMR光谱谱图在20ppm和170ppm处出现聚乳酸特征的碳吸收峰,说明剩余物中含有聚乳酸和淀粉的接枝物。由共混物中聚乳酸的端羧基含量的测定结果也能说明酯化反应后共混物剩余物中含有聚乳酸和淀粉的接枝物。考察了生成的接枝物对共混体系相容性的影响,扫描电镜分析结果表明,经过预处理酯化反应后共混物相容性得到了提高。挤出样条取向拉伸后进行力学性能测试,发现酯化反应明显提高了力学性能。该方法可以通过设计共混挤出过程实现改变共混物相容性的目的,具有广阔的前景和很强的应用价值。     

离子液体增塑改性玉米淀粉/聚丁二酸丁二醇酯共混材料的结构与性能

为考察离子液体对淀粉/聚丁二酸丁二醇酯(PBS)的作用效果,降低淀粉/PBS的脆性,以离子液体(1-丁基-3-甲基咪唑氯盐[BMIM]Cl)作为增塑改性剂通过熔融共混法制备了玉米淀粉/聚丁二酸丁二醇酯(PBS)共混材料,采用红外光谱(FTIR)、扫描电镜(SEM)、热重分析(TGA)、X射线衍射分析(XRD)及力学性能测试方法研究了[BMIM]Cl对淀粉/PBS共混材料结构和性能的影响.结果表明,[BMIM]Cl能与淀粉/PBS分子发生强相互作用,破坏淀粉/PBS共混物中原有的氢键与结晶结构,增强界面相互作用,改善相容性,进而改变淀粉/PBS共混材料的结构与性能;[BMIM]Cl的加入不影响淀粉/PBS的热稳定性,可使材料玻璃化转变温度(Tg)、结晶温度(Tc)、冷结晶温度(Tcc)及结晶度(Xc)降低.[BMIM]Cl具有显著降低淀粉/PBS脆性的作用,使其断裂伸长率大幅度增加,拉伸强度和弹性模量降低.     

淀粉-丙烯酸钠接枝共聚物的固体高分辨核磁共振研究

运用固体高分辨核磁共振技术,通过测量13C魔角旋转/交叉极化(CP/MAS)谱、1H自旋-晶格弛豫时间T1及旋转坐标系中的自旋-晶格弛豫时间T1ρ,对一系列淀粉-丙烯酸钠接枝共聚物的相结构进行了研究,并与淀粉、均聚丙烯酸钠及两者共混物的实验结果进行了比较.结果表明,接枝共聚导致了淀粉结晶度的明显降低;在共混物和接枝共聚物中,淀粉和聚丙烯酸钠组分都具有纳米尺度的相容性,由于接枝的效应,接枝共聚物中两个组分表现出比共混物更高的相容水平.     

接枝聚乳酸/塑化淀粉共混物的制备与性能研究

为提高聚乳酸(PLA)/淀粉共混物界面作用和降低成本,引入甲基丙烯酸缩水甘油酯(GMA)接枝聚乳酸和塑化淀粉(TPS),通过挤出和注射成型制备接枝聚乳酸/塑化淀粉共混物(PLA-g-GMA/TPS)。红外光谱分析证实,GMA成功接枝到PLA分子链上。对共混物的力学性能、热机械性能、微观形貌、热性能及亲水性等进行了系统研究,结果表明,选择GMA用量为6%(接枝率为1.51%)和TPS用量为10%时的拉伸强度、断裂伸长率及弹性模量最佳,分别为42.6MPa、8.9%及260MPa。FE-SEM观察结果表明,低含量TPS中颗粒被基体包覆或嵌入,界面平整,界面结合力强。DMA和DSC结果显示,不同质量配比的PLA-g-6%GMA/TPS共混物的Tg、储存模量、结晶度、结晶温度及熔融温度仅在小范围内发生变化。吸水率和接触角结果表明,低含量TPS的共混物吸水率和接触角变化幅度均小于高含量TPS体系。     

Blends of starch with ethylene vinyl alcohol copolymers: effect of water,glycerol, and amino acids as plasticizers

Blends of thermoplastic starch with poly(ethylene‐co‐vinyl alcohol) copolymer (EVOH) were melt extruded with water/glycerol as plasticizer and a series of amino acid additives. The biggest factor in end‐use mechanical properties proved to be the relative humidity (RH) during storage. Plasticized starch‐EVOH blends stored at 0 and 50% RH changed significantly over time, with, for example, the tensile strength (TS) of the glycerol‐plasticized blend increasing from 4.7 to 26.3 MPa over 8 weeks when maintained at 0% RH. In contrast, the TS of this same sample stored at 75% RH remained unchanged for 8 weeks. Amino acids provided relatively minor, but significant changes in mechanical properties with time. Based on TS, elongation‐to‐break, and modulus, it may be concluded that β‐alanine, sarcosine, and L ‐proline were more effective than glycerol at maintaining strong flexible blends. Increases in crystallinity and changes in morphology with time, as described by modulated DSC were correlated to these changes in mechanical properties. Published in 2007 by John Wiley & Sons, Ltd.     

A Concise Review on the Physicochemical Properties of Biopolymer Blends Prepared in Ionic Liquids

An enhancement of environmental concern lately has improved the awareness of researchers in employing eco-friendly solvents for processing biopolymers. Recently, ionic liquids have been utilized to prepare biopolymer blends as they are non-volatile and recyclable. Biopolymers such as cellulose, chitin, chitosan, keratin, lignin, silk, starch, and zein are widely used for the preparation of biopolymer blends via dissolution in ionic liquids, followed by coagulation procedure. In this concise review, three types of ionic liquids based on imidazolium cations combined with different counter anions that are frequently utilized to prepare biopolymer blends are described. Moreover, three types of biopolymer blends that are prepared in ionic liquids were classified, specifically polysaccharide/polysaccharide blends, polysaccharide/polypeptide blends, and polysaccharide/bioplastic blends. The physicochemical properties of biopolymer blends prepared in different imidazolium-based ionic liquids are also concisely reviewed. This paper may assist the researchers in the polymer blend area and generate fresh ideas for future research.     

The microstructural characterization of PA6/PA12 blend specimens fabricated by selective laser sintering

This study investigates the processing of blends of polyamide 6 (PA6) and polyamide 12 (PA12) by selective laser sintering (SLS) using a CO₂ laser. Powder properties of undiluted polymers, mixture composition, and processing parameters, as well as their influence on the microstructure of the specimens manufactured, were evaluated. Polyamides showed higher absorption of laser energy during the sintering of blend specimens, with subsequent thermal energy transfer to the melting of the polymeric phases. The structure of parts obtained by SLS is dependent on the process parameters and the characteristics of the powder material to be processed. The microstructures of PA6/PA12 blend specimens were heterogeneous, with co-continuous and disperse phases depending on the quantity of PA12. The porosity and crystallinity also changed as a function of the component proportions. The use of polymeric blends can increase the range of structures and properties of SLS parts.     

Preparation and Characterisation of Thermoplastic Starches from Cassava Starch,Cassava Root and Cassava Bagasse

Summary: Thermoplastic starches (TPS) based on cassava starch have been produced by extrusion at 120 °C, using glycerol as plasticizer. Three forms of cassava starch were employed, viz: cassava root (CR), cassava bagasse (CB) and purified cassava starch (PCS). The main differences between these are the presence of sugars and a few fibres in CR and high fibre concentration in CB. Conditions of processing and characteristics such as amylose and fibre content, crystallinity, water absorption and mechanical behaviour in the tension x deformation test were evaluated. The results demonstrated that the PCS and CR had amylose contents consistent with literature values (14–18%) and that CB is a material constituted mainly by amylopectin. It was found that fibres in high proportions (as in the bagasse) can confer reinforcement properties and are thus able to generate natural composites of TPS with cellulose fibre. The sugars naturally found in the root reduce the elongation of the TPS under tension. The PCS and CR TPS were stable with respect to indices of crystallinity after processing; and during a period of 90 d in a relative humidity of 53%, while the CB TPS tended to vary its crystallinity, probably because its amylose chain had low degree of polymerization.     

Synthesis and investigation of polyethylene blends with natural polysaccharides and their derivatives

Powder blends of LDPE with cellulose, ethyl cellulose, starch, chitin, and chitosan have been prepared under shear deformation in a rotor disperser at different initial-component ratios. The composition of powder fractions is identical to the original composition of the blends. The studied polymer blends demonstrate high mechanical characteristics. X-ray diffraction analysis and DSC studies show that the blending of LDPE with polysaccharides under shear deformations results in changes in the polymer structure and leads to a decrease of their degree of crystallinity. The maximum intensity of mold fungi growth is observed in starch-LDPE (50: 50, wt/wt) and chitin-LDPE (50: 50, wt/wt) blends.     

Improving the Processing Ability and Mechanical Strength of Starch/Poly(vinyl alcohol) Blends through Plasma and Acid Modification

Summary: In this study, 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 starch/poly (vinyl alcohol) (PVA) blends were studied. The melt flow index (MFI) of starch/ glycerol/PVA (300g/60g/80g) blend was increased from 2.3g/10min to 32.7g/10min by adding 3g of MA and to 130 g/10min by adding MA and plasma treatment. The tensile strength of starch/glycerol/PVA blend increased from 3.48 to 6.21 MPa by adding 1.5g of MA and 1.5g of CA, while it increased to 6.26 MPa by plasma treatment. Esterification reaction which was evidenced by FTIR has been showed to improve the compatibility between starch and PVA when MA was dissolved into glycerol and glycerol grafted onto plasma pretreatment PVA. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) imaging were used to study the morphology of extruded blends.     

Crystallinity and rheology of HDPE/PA12 blends compatibilized with HDPE-alt-MAH

This work studies the crystallinity and rheology of HDPE/PA12 blends compatibilized with 2 wt% of HDPE-alt-MAH. Specimens of HDPE/PA12 blends were extruded and injected into a mold with 75/25, 50/50, and 25/75 HDPE/PA ratios. The Fourier-transform infrared spectroscopy (FTIR) analysis showed that no oxidation reaction occurred in the high-temperature processing and that stronger interactions between the components of the blends occurred in the polyamide's functional groups. The x-ray diffraction (XRD) analysis showed that the crystallinity degree of the blends and the mean crystallite sizes decreased with the addition of PA12 for both blends. The HDPE's lattice parameters were consistent with the values in the literature, whereas for the PA12, it was not possible to fit its lattice parameters. The rheology analysis evaluated the relationship between the shear stress and viscosity and found that the HDPE/PA 75/25 blend was the most pseudoplastic, presenting the best processability under high shear rates.