Physicochemical Studies on Interaction Behavior of Potato Starch Filled Low Density Polyethylene Grafted Maleic Anhydride and Low Density Polyethylene Biodegradable Composite Sheets

Study presents compatibility behavior of polar group potato starch and non-polar LDPE using 50%, 0.5% maleated LDPE. The aim was to improve intermolecular interaction between two different types of moieties (LDPE and Potato Starch). Samples were prepared by mixing potato starch (upto 30% by weight) with LDPE and LDPE-grafted maleic anhydride in a single step twin screw extruder having vent zone. XRD and DSC results suggested that maleic-anhydride group of LDPE helped the interaction with starch and brought two chemical moieties closer to each other. FTIR results also strongly supported new bond formation between two chemical moieties.     

胶粉/低密度聚乙烯复合材料的性能研究简

采用全轮胎废胶粉(WRP)/低密度聚乙烯(LDPE)(并用比65/35)制备橡塑复合材料。研究增容剂和交联体系对WRP/LDPE复合材料物理性能的影响。结果表明:乙烯-乙酸乙烯酯对WRP/LDPE复合材料的增容效果较好;交联体系采用过氧化二异丙苯且用量为1份时WRP/LDPE复合材料物理性能较好。     

Mechanical,Water Absorption and Enzymatic Degradation Properties of Sago Starch Filled Linear Low Density Polyethylene

Abstract

Sago starch filled linear low density polyethylene (LLDPE) composites, have been prepared by melt mixing of the granular starch and LLDPE in a HAAKE internal mixer. The tensile, water absorption and enzymatic degradation properties of the composites have been determined. Incorporation of sago starch into LLDPE led to decrease in tensile strength and elongation at break of the composites. Up to 15 wt.% of sago starch could be added to LLDPE without adverse effects on the tensile properties. The water uptake increased with immersion time and the rate of absorption is strongly controlled by the immersion temperatures. Dramatic reduction in tensile properties were observed in the composites that were immersed in water at 90[ddot]C. The recovery of the tensile strength and elongation at break upon redrying is about 37.5 and 1.6% respectively. The permanent damage to the composites was attributed to severe hydrolysis of the starch particles. The enzymatic degradation study using oc-amylase revealed that both tensile strength and elongation at break reduced with time of treatment. Mode of failures of both LLDPE matrix and its sago starch filled composites, assessed by fracto-graphic analysis in a scanning electron microscope (SEM) are discussed.     

Effect of Vinyl Alcohol-Phthalic Anhydride on Properties of Low Density Polyethylene (LDPE)/Tyre Dust (TD) Composites

The effect of vinyl alcohol-phthalic anhydride as a coupling agent on the tensile properties, morphology, and thermal degradation of low density polyethylene/tyre dust (LDPE/TD) composites was studied. LDPE/TD composites with different tyre dust loading and the addition of vinyl alcohol-phthalic anhydride were prepared with Z-blade mixer at 180°C and rotor speed of 50 rpm. The result indicated that LDPE/TD_M composites with vinyl alcohol-phthalic anhydride show higher values of tensile strength, Young's modulus and mass swell, but lower elongation at break than LDPE/TD composites without vinyl alcohol-phthalic anhydride. The SEM micrographs showed that the tyre dust was more widely dispersed in the LDPE matrix with the addition of vinyl alcohol-phthalic anhydride as a coupling agent. It was also found that the addition of vinyl alcohol-phthalic anhydride offers better thermal stability in the LDPE/TD_M composites than LDPE/TD composites.     

LDPE/PEG插层剥离改性氮化硼导热复合材料的制备及其性能

以聚乙二醇(PEG)为插层剂,通过机械球磨法制备了PEG插层剥离改性氮化硼。以低密度聚乙烯(LDPE)为基体,PEG插层剥离改性氮化硼为导热填料,采用双辊开炼、压片成型制备LDPE/PEG插层剥离改性氮化硼导热复合材料,研究了改性氮化硼用量及粒径对复合材料导热性能、力学性能和电绝缘性能的影响。结果表明:随着PEG插层剥离改性氮化硼用量的增加,复合材料的导热性能提高,拉伸强度和弯曲强度提高,悬臂梁缺口冲击强度下降;粒径较大的PEG插层剥离改性氮化硼对复合材料导热性能的提高更显著;复合材料的表面电阻下降,但仍保持在1010数量级,具有优异的电绝缘性能。     

Biodegradable Composition Based on Low Density Polyethylene

ABSTRACT

Sodium salt of partially carboxymethylated starch (Na-PCMS) with degree of substitution DS 0.58 and starch acetate with DS 1.7 were synthesized from starch. These starch ethers and acetates along with starch, poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVA) were blended with low density polyethylene (LDPE) in various proportion using Brabender mixer. Addition of 5% stearic acid as a plasticizer improves the blend compatibility. Change in mechanical properties were monitored and optimum composition of blend were prepared. This blend was studied for growth of Bacillus species (BS) and degradation by means of weight loss and change in mechanical properties viz., tensile strength and % elongation, and total cellular protein. Degradation of pure polymers within one month period was also examined.     

Effect of Polyethylene-Grafted Maleic Anhydride (PE-g-MAH) on Properties of Low Density Polyethylene/Eggshell Powder (LDPE/ESP) Composites

The effect of polyethylene-grafted maleic anhydride (PE-g-MAH) on the tensile properties, morphology and thermal properties of low-density polyethylene (LDPE)/eggshell powder (ESP) composites was studied. LDPE/ESP composites with different eggshell powder content and the addition of PE-g-MAH were prepared with Z-blade mixer at 180°C and rotor speed of 50 rpm. The tensile strength, elongation at break and thermal stability of LDPE/ESP composites with PE-g-MAH were greater than LDPE/ESP composites, and their differences became more pronounced at higher filler content. The interfacial adhesion between ESP and LDPE was improved with the addition of PE-g-MAH as evidenced by the morphological study.     

线性双峰聚乙烯／低密度聚乙烯共混物的流变行为与力学性能

研究了线性双峰聚乙烯（LBPE）与低密度聚乙烯（LDPE）共混物溶体的流变行为，讨论了共混物的组成，剪切应力和剪切速率以及温度对熔体流变行为，熔体粘度的影响，测定了不同配比熔体的非牛顿指数（n)，熔体流动速率（MFR）及力学性能，为双峰聚乙烯的加工和使用提供了理论依据。     

Morphology,thermomechanical properties,and biodegradability of low density polyethylene/starch blends

The biodegradability of low density polyethylene (LDPE)/starch and LDPE/starch/starch acetate (STAc) blends was tested and observed to be dependent on STAc content. The binary and ternary blends containing up to a maximum concentration of 30% starch were examined for their thermal, mechanical, and morphological properties. The blends with no STAc or 2.5% STAc show almost no adherence of two phases. With 10% STAc, dispersion of starch was observed to increase with some adherence to LDPE. Tensile strength, elongation at break, and Izod impact strength of the blends decreased with increased starch content. However, incorporation of STAc along with starch improved all these properties, particularly elongation at break and toughness. The melt flow index was also improved on partial substitution of starch by STAc. Maximum biodegradability was observed for the blends containing 30% (starch + STAc). Cell growth was observed to increase with increasing concentration of (starch + STAc) in the blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2791–2802, 1999     

LLDPE/LDPE/TiO2复合膜的分散及光学性能

讨论了纳米TiO2在线型低密度聚乙烯（LLDPE），低密度聚乙烯（LDPE）复合体系中的分散和体系流变行为，研究了复合薄膜的光学性能。结果表明，以高流动性LDPE为基体的纳米TiO2母料，加入LLDPE，LDPE体系中后。复合体系的表观粘度有所提高。但拉伸粘度显著下降。纳米TiO2母料在LLDPE／LDPE复合体系中具有良好的分散性，复合薄膜中的纳米TiO2为一次粒子。纳米TiO2起到了异相成核剂的作用。球晶的粒子得到细化。在本研究的纳米填充范围内（质量分数不大于1.0％），复合薄膜的透光度基本不变。雾度发生了较大幅度上升，复合薄膜在紫外光区域的吸收显著增强。     

Effect of Poly(methyl Methacrylate) Modified Water Hyacinth Fiber on Properties of Low Density Polyethylene/Natural Rubber/Water Hyacinth Fiber Composites

The effect of poly(methyl methacrylate) modified water hyacinth fiber on properties of low density polyethylene (LDPE)/natural rubber (NR)/water hyacinth fiber (WHF) composites were investigated. The composites were prepared with Z-blade mixer at 180°C and rotor speed of 50 rpm. The poly(methyl methacrylate) modified water hyacinth fibers in LDPE/NR composites (LDPE/NR/WHF-_PMMA) gave a greater value of tensile strength, Young's modulus, glass transition temperature (Tg), melting temperature (Tm), and % crystallinity compared to unmodified water hyacinth fibers in LDPE/NR composites (LDPE/NR/WHF). FTIR analysis shows the presence of ester carbonyl group and C-O ester group in poly (methyl methacrylate) modified water hyacinth fiber. The SEM micrograph also shows a better interfacial adhesion between the fibers and LDPE/NR matrixes for LDPE/NR/WHF-_PMMA composites than LDPE/NR/WHF composites. LDPE/NR/WHF-_PMMA composites had a lower value of interparticle spacing compared to LDPE/NR/WHF composites thatenhanced the interparticle interaction between fiber and LDPE/NR matrixes.     

Electrical Properties of 10 MeV Electron Beam Irradiated and Aged Low Density Polyethylene

Polymers play a very important role in electrical systems as insulation materials. The microscopic failures occurring in the polymer under working conditions will be important in its required characteristics. In this work we focused on the effects of accelerated aging on the electrical properties of low density polyethylene (LDPE) and crosslinked polyethylene (XLDPE). The samples of LDPE were prepared in sheet form with the thickness of 0.6 ± 0.1 mm and were irradiated under the 10 MeV electron beam of a Rhodotron accelerator at the dose range of 70 to 370 kGy. Then, the samples were stored in an oven at temperature 75°C for 3, 6, 10 and 13 days. Electrical properties such as the breakdown voltage and resistance of the aged samples were measured and compared. Increasing the aging time for unirradiated samples has a serious and moderate influence on their surface resistivity and breakdown voltage, respectively. The results indicated a maximum value for the surface resistance at the optimum radiation absorbed dose, which is approximately 220 kGy for all the samples.     

Study on Mechanical and Dielectric Properties of Jute Fiber Reinforced Low-Density Polyethylene (LDPE) Composites

Abstract

Jute fiber (Hessian cloth) reinforced low-density polyethylene (LDPE) composites were prepared by heat press molding techniques. The mechanical properties such as tensile strength (TS), bending strength (BS), and elongation at break of the composites were studied. The enhancement of TS (33%) and BS (50%) were obtained as a result of reinforcment jute fabrics in LDPE. In order to improve the mechanical properties and adhesion between jute and LDPE, hessian cloth were each treated with 2-hydroxyl ethyl methacrylate (HEMA). The HEMA-treated jute composite showed higher tensile and bending strength compared to untreated jute composite and LDPE. Dielectric properties like dielectric constant and loss tangent (tan δ) of jute, LDPE and composites were studied. Ferro to paraelectric phase transition occurred in both treated and untreated jute composites containing more than 20% jute. Water uptake behaviors of the composite were monitored and HEMA-treated composite showed lower water absorption behavior. The adhesion nature of jute and LDPE also characterized by scanning electronic microscopy (SEM), better adhesion was observed between HEMA-treated jute and LDPE over untreated ones.     

改性LDPE高发泡弹性材料的研究

以低密度聚乙烯（LDPE）为基体原料,乙烯-辛烯共聚物（POE）为增韧材料,CaCO3为填充料,硼酸酯为改性剂,添加AC发泡剂、DCP交联剂等助剂;采用界面改性、密炼塑化、模压发泡方法制备改性LDPE高发泡弹性材料,并对其性能进行分析研究。结果表明：含LDPE70质量份、POE30质量份、改性CaCO310质量份、AC2质量份、DCP1.4质量份的发泡材料,其拉伸强度2.40MPa、撕裂强度5.82KN/m、断裂伸长率163.2%、密度0.236g/cm3、收缩率1.1%,物理力学性能优良。     

Effects of Durian Seed Flour on Processing Torque,Tensile, Thermal and Biodegradation Properties of Polypropylene and High Density Polyethylene Composites

Composites containing various percentage of durian seed flour (DSF) in the polypropylene (PP) and high density polyethylene (HDPE) have been compounded using an internal mixer. The processing torque, tensile, thermal and biodegradation properties have been determined. The incorporation of DSF increases stabilization torque and had adversely affected the mechanical properties by reducing the tensile strength and elongation at break, while the elastic modulus is increased, as starch content increases. At similar filler content, DSF filled PP showed higher tensile strength and elastic modulus, while lower in elongation at break than DSF-filled HDPE. The scanning electron microscopy (SEM) of tensile fracture specimens revealed good adhesion and dispersion of the DSF granules in the polymer matrix. However, the SEM results showed agglomeration of the DSF at higher filler content in the polymer and hence revealed poor wetting between DSF granules and polymer. The TGA results showed that both of the composites systems with higher filler content have higher initial degradation temperatures, T₀, degradation temperatures, T_deg and total weight loss. A simple biodegradability test conducted on each composite system shows that composites are subjected to biodegradation, judging by the significant increase in carbonyl and hydroxyl index of the composites after the test.     

Composites of Low-Density Polyethylene and Castor Presscake

Composites of low density polyethylene were prepared by melt mixing in a co-rotating twin screw extruder. Castor presscake, a biodiesel process co-product, was used as filler for the polyethylene composites. Different concentrations of this filler were added to the polymer matrix. Melt flow index and. mechanical properties were measured by following standardized tests. The results showed that the addition of the filler to the polymer matrix provoked an increase on the values of Young Modulus and on the flexural properties. However, the impact strength and the tensile stress values tended to decrease with the increasing of the filler concentration.     

Effective Control of Laser‐Induced Carbonization Using Low‐Density Polyethylene/Polystyrene Multilayered Structure via Nanolayer Coextrusion

Controlled carbonization is very critical in improving the effect of laser‐induced patterns on a polymer surface. In the present work, the effects of a multilayered structure on the physical and laser‐marking properties of a low‐density polyethylene/polystyrene (LDPE/PS) multilayered film are studied. The multilayered film is prepared using nanolayer coextrusion and treated in air by scanning with a neodymium‐doped yttrium aluminum garnet (Nd:YAG) pulsed laser beam. Based on various analyses, the laser‐induced patterns on the LDPE/PS multilayered film are significantly different from those on a conventional LDPE/PS blend. Furthermore, a mechanism for controlling the carbonized area of a multilayered film is proposed. This study also provides an effective method to fabricate laser‐patterning polymer materials based on a multilayered structure. Nanolayer coextrusion will have broad application prospects in the field of polymer laser marking. Importantly, this work opens up a valuable and viable direction for the practical application of these multilayered polymer materials.     

低密度聚乙烯生产技术

本文重点叙述了管式法生产低密度聚乙烯（ＬＤＰＥ）的技术及其进展，并介绍了国内外各大公司ＬＤＰＥ的生产情况。     

Effects of Heating,Tensile, and High Pressure Treatments on Aggregate Structure of a Low Density Polyethylene

The effects of heating, tensile, and high pressure treatments on the aggregate structure of a low density polyethylene (LDPE) are studied via modulated DSC (MDSC) and dynamic mechanical technique (DMA). The results indicate that the nonreversing heat flow can reflect the relative thermodynamic stability for crystalline structure of the polymer, and this makes nonreversing heat flow be a novel useful tool to qualitatively characterize the perfect degree of crystalline structures. During thermal treatment, it is found that there exists a low temperature melting endotherm at about 35°C. It presents an endothermal peak in nonreversing heat flow and a simultaneous glasslike transition in reversing heat flow, which behaves a feature of physical aging far above the glass transition temperature of the polymer. This suggests the existence of so-called “rigid amorphous fraction” (RAF). The structural changes of polyethylene induced by different treating methods are also investigated by DMA, and the relaxation characteristics of macromolecular chains are analyzed.     

The Effect of NCO-Polyol on the Properties of Low-Density Polyethylene/Water Hyacinth Fiber (Eichhornia crassiper) Composites

Low density polyethylene (LDPE)/modified water hyacinth fiber (WHF) composites have been prepared by melt blending. All the composites were characterized by tensile test, differential scanning calorimetry (DSC), water absorption behaviour, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results indicated that LDPE/WHF composites with NCO-polyol as a coupling agent show higher values of tensile strength, Young's modulus and water absorption resistance but lower elongation at break than LDPE/WHF composites without NCO-polyol. The micrographs of SEM showed that the WHF were more widely dispersed in the LDPE matrix with the addition of the NCO-polyol as a coupling agent. It was also found that the modified WHF offers better thermal stability in the LDPE/WHF composites than unmodified WHF.