尼泊金乙酯——改性LDPE抑菌薄膜制备与性能研究

研究尼泊金乙酯(ELN)的添加量对改性低密度聚乙烯(LDPE)抑菌薄膜性能的影响,将ELN添加到改性LDPE树脂和LDPE树脂中,通过共混、吹塑等工艺制备出ELN—改性LDPE抗菌薄膜,并研究ELN添加量对抑菌薄膜的机械、光学、氧气透过率、结构表征,抗菌等性能的影响。结果表明,随着ELN添加量的增加,薄膜的断裂伸长率先增加再减小,透光率逐渐下降,雾度逐渐上升,薄膜的氧气透过率和水蒸气透过系数先下降后上升,热稳定性先升高后降低。ELN的质量分数0.5%时,大肠杆菌和金黄色葡萄球菌的抑制作用显著增强。ELN的添加能提高薄膜的综合性能和抑菌效果,对研究新型包装材料具有重要的意义。     

不同无机填料及其含量对LDPE薄膜性能的影响

目的研究纳米TiO_2、纳米级ZSM-5分子筛、微米级ZSM-5分子筛这3种无机填料对LDPE(低密度聚乙烯)薄膜的力学性能的影响。方法将不同无机填料通过双螺杆挤出机与LDPE造粒后,通过单螺杆挤出机挤出流延成膜,并考察薄膜的性能。结果制备的薄膜厚度为91~174μm,实验结果表明,无机填料的加入使LDPE薄膜的拉伸强度及断裂伸长率有不同程度的降低,氧气透过系数增加了17.3%~60.5%,添加填料的LDPE薄膜的二氧化碳透过系数是空白膜的1.3~3倍,ZSM-5分子筛的添加对薄膜的水蒸气透过系数有所提升,而二氧化钛的添加则导致水蒸气透过系数下降。结论无机填料的加入提升了LDPE薄膜的透气性能,但是还需要更进一步的改性,更大程度地改善其透气性、水蒸气透过性和力学性能。     

载银抗菌剂 / LDPE 抗菌薄膜的制备与性能研究

将载银抗菌剂粉末添加到低密度聚乙烯树脂中,通过共混、吹塑等工艺,制备出了抗菌薄膜。 研究表明,随着载银抗菌剂含量的增加,抗张强度和伸长率的变化趋势为先增大再减小,透过率逐渐减小,摩擦系数则逐渐增大,透湿系数变化趋势为先减小再增大。 扫描电镜?毂砻?抗菌剂在基体树脂中分散均匀。 以金黄色葡萄球菌为指标的抗菌性能测试表明,载银抗菌薄膜具有较好的抗菌性。     

纳米ZnO-T树脂改性聚乙烯薄膜的制备和性能

以低密度聚乙烯为基材,将改性T树脂和改性纳米ZnO加入其中,利用双螺杆造粒机以及流延机通过熔融共混制得改性聚乙烯薄膜,并研究改性T树脂和改性纳米ZnO的含量对聚乙烯薄膜的抑菌效果、水蒸气透过量、氧气透过量、力学性能、微观结构、红外光谱及紫外透过率的影响。结果表明,当加入1.5%的改性纳米ZnO时,薄膜的抑菌性能随改性T树脂含量的不断增大而更加显著,紫外线透过率的变化趋势为先降低后上升。当改性纳米ZnO的质量分数为1.5%、改性T树脂的质量分数为1%时,水蒸气透过量和氧气透过量最小,抗拉强度和断裂伸长率最大。薄膜的阻隔性效果和抑菌性能较好,可应用于食品包装,延长食品的保质期。     

LDPE/LLDPE/分子筛保鲜包装膜的力学性能和摩擦性能研究

以低密度聚乙烯(LDPE)和线性低密度聚乙烯(LLDPE)(质量比为80∶20)作为基础物质,添加不同比例的分子筛,吹制保鲜膜,研究了保鲜膜的力学性能和摩擦性能。研究表明:随着分子筛含量的增加,薄膜的拉伸强度、伸长率、耐戳穿强度和撕裂强度均出现一定程度的下降;加入分子筛之后,保鲜膜的摩擦系数上升。     

LDPE / LLDPE / EVA 三元共混膜的力学性能和摩擦性能研究

以低密度聚乙烯(LDPE)和线性低密度聚乙烯(LLDPE)作为基础物质,添加乙烯-醋酸乙烯酯共聚物(EVA),吹制保鲜膜,研究了保鲜膜的力学性能和摩擦性能。研究表明,复合膜的拉伸强度、伸长率、耐戳穿强度和撕裂强度随着EVA含量的增加,总体呈下降趋势,摩擦系数则逐渐上升。     

聚乙烯结晶度对银抗菌剂溶出的影响EI

采用双螺杆挤出的方法制备了低密度聚乙烯(LDPE)/玻璃载体银系抗菌剂(IONPURE)的抗菌塑料。用溶出伏安法测定了抗菌塑料中银离子的溶出速率,用差示扫描量热法(DSC)研究了抗菌LDPE的熔融和结晶行为,用XRD和POM对LDPE的晶形和结晶度进行了表征,结果表明,抗菌剂在LDPE中起到异相成核的作用,随着其含量从0%增加到8%,LDPE结晶度呈现先增加后下降的趋势,而晶粒尺寸则逐渐减小。同时,通过加速溶出实验研究了不同结晶度抗菌LDPE样品中银离子的溶出行为,发现样品结晶度越大,银离子溶出速率越小,并且随着在水中浸泡时间的延长,结晶度影响越发明显。     

聚乙烯结晶度对银抗菌剂溶出的影响

采用双螺杆挤出的方法制备了低密度聚乙烯(LDPE)/玻璃载体银系抗菌剂(IONPURE)的抗菌塑料。用溶出伏安法测定了抗菌塑料中银离子的溶出速率,用差示扫描量热法(DSC)研究了抗菌LDPE的熔融和结晶行为,用XRD和POM对LDPE的晶形和结晶度进行了表征,结果表明,抗菌剂在LDPE中起到异相成核的作用,随着其含量从0%增加到8%,LDPE结晶度呈现先增加后下降的趋势,而晶粒尺寸则逐渐减小。同时,通过加速溶出实验研究了不同结晶度抗菌LDPE样品中银离子的溶出行为,发现样品结晶度越大,银离子溶出速率越小,并且随着在水中浸泡时间的延长,结晶度影响越发明显。     

转光薄膜对绿颜色蔬菜品质影响的研究

目的延长绿颜色蔬菜的货架寿命,保护绿色蔬菜品质。方法模拟某超市果蔬区的销售环境,以鲜切西兰花为例,选择单基双能转光剂(RBI),吹制添加质量分数为0.5%,0.8%,1.2%,1.5%,2.0%的低密度聚乙烯(LDPE)薄膜。对转光薄膜的气体透过性和光学性能进行测试,分别将添加不同含量单基双能转光剂的LDPE薄膜包装鲜切西兰花,并置于模拟超市的光照环境下,测定试验样品的质量、维生素C含量、叶绿素含量等变化,并对试验样品进行感官评价。结果对比超市现有绿颜色蔬菜的包装薄膜,在LDPE薄膜中添加适量转光剂可以达到保护鲜切西兰花品质、延长其货架寿命的效果。结论添加质量分数为1.2%单基双能转光剂的低密度聚乙烯薄膜的保鲜效果最好。     

全同聚1-丁烯/低密度聚乙烯共混体系的流变性能

采用双毛细管流变仪研究了全同聚1-丁烯/低密度聚乙烯(iPB/LDPE)共混体系的流变性能。结果表明,随着iPB用量的增加,共混熔体的剪切黏度呈先下降后上升的趋势;iPB/LDPE共混熔体在剪切速率为100 s-1~1000 s-1时,为假塑性流体,且随着iPB含量增加和温度升高,其非牛顿性增大;共混体系的表观黏度随剪切速率和剪切应力的增大、温度的升高而减小;粘流活化能随剪切速率的增大呈逐渐减小的趋势。     

Effect of High Pressure Processing on the Thermal and Mechanical Properties of Polyethylene Films Measured by Dynamical Mechanical and Tensile Analyses

This study investigated the influence of high pressure processing on the thermal and mechanical properties of low‐density polyethylene (LDPE) films used for food packaging. This was carried out by monitoring the thermal and mechanical properties of the materials before and after the pressure treatments. Pouches made from the LDPE films were pressured at 200, 400 and 800 MPa for 5 and 10 min at 25 and 75°C. The storage and loss moduli, tensile strength and elongation at break and yield of the film samples were then measured using dynamic mechanical analysis (DMA) and an Instron® Universal Tester (Canton, MA, USA), respectively. The DMA was performed at ?130 to 85°C, whereas the tensile and elongation analyses were carried out at room temperature. Results of the DMA experiments showed that the storage modulus increased with increasing pressure intensity. The tensile analysis showed that the tensile strength increased but the elongation decreased with increasing pressure treatment. Copyright © 2013 John Wiley & Sons, Ltd.     

石墨烯/低密度聚乙烯复合膜的制备及性能

目的以石墨烯/低密度聚乙烯(LDPE)复合包装材料为研究对象,讨论石墨烯、石墨烯微片对低密度聚乙烯薄膜力学性能、颜色、透光率及透氧率的影响。方法使用熔融共混方法制备不同石墨烯质量分数的石墨烯/LDPE复合材料,检测并比较其性能变化。结果石墨烯以及石墨烯微片的加入,使LDPE薄膜的弹性模量提高了9%~50%,横纵向拉伸强度提高了2%~30%,透光率降低了10%~60%,透氧率提高了10%~15%。结论由于石墨烯比表面积大、刚性高,对LDPE材料的拉伸强度、弹性模量等力学性能有明显改善,同时可提高薄膜透氧率,加深LDPE材料的颜色,降低薄膜透光率。     

The effect of process parameters on physical and mechanical properties of commercial low density polyethylene/ORG-MMT nanocomposites

Polyethylene/organo-montmorillonite clay (org-MMT) nanocomposites were prepared utilizing PP-g-MA as a compatibilizer by melt intercalation method. In order to increase the miscibility of polyethylene (PE) with nanoparticle surface at firs, a primary masterbatch consist of compatibilizer and org-MMT was prepared then, this compound was melt intercalated with PE to synthesis the PE/org-MMT nanocomposites. In this study, the presence of commercial low density polyethylene in Nanocomposites structure and also the effect of process parameters such as: amount of nanoparticles, mixing rate and mixing time on nanocomposite structure and properties have been investigated. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that the interlayer distance of nanoparticle layers increased and a partially intercalated structure was prepared by melt intercalation method. Interaction between polyethylene chains and nanoparticle layers could be improved if the control of above parameters causes to penetrate the chains into nanoclay layers; by an optimization, this effect could improve the physical and mechanical properties. The DSC data revealed that melting temperature has slowly increased and crystalinity has lightly decreased. Consequently we can claim the thermal properties of LDPE/clay nanocomposite did not considerably change with clay content. A rise in the mechanical properties such as yield stress and modulus was observed by tension test; by addition of 5% clay content the tensile strength increased about 7%, the tensile modulus enhanced about 60% and the yield stress increased about 16% in comparison with the pure LDPE.     

Development of an Active Thermoplastic Film with Oxygen Scavengers Made of Activated Carbon and Sodium Erythorbate

An active thermoplastic film made of low‐density polyethylene (LDPE) filled with oxygen scavengers made of powdered activated carbon (PAC) impregnated with sodium erythorbate (SE) was developed for packaging applications. Initial tests indicated that the impregnation of PAC with SE enhanced the heat resistance of SE, thereby allowing processing at temperatures typical of LDPE manufacturing. Subsequently, LDPE films with PAC/SE particles were manufactured in coupons that represented a typical juice package, and experiments indicated that these films absorbed 3.57 mg of oxygen in 11 days. This amount corresponded to 80% the concentration of oxygen in the headspace of the package. Furthermore, findings indicated that active particles alone have 10 times higher oxygen absorption capacity than the active LDPE film. Finally, the physical properties of the film were characterized by microscopy where oxygen scavengers showed a good dispersion within the matrix. However, 20 wt.% of these active particles decreased tensile strength of the film by 53%. Copyright © 2014 John Wiley & Sons, Ltd.     

可食性干酪包装膜的制备及性能研究

目的研究酪蛋白酸钠、壳聚糖、甘油添加量对可食膜性能的影响。方法以酪蛋白酸钠和壳聚糖为原料,甘油作为增塑剂,制备可食性干酪包装膜,以膜的水溶性及力学性能为指标,通过单因素及正交试验,确定各成膜成分的最佳配比。结果当用质量分数为5%的酪蛋白酸钠水溶液、质量分数为2%的壳聚糖冰乙酸溶液和质量分数为2%的甘油混合液进行成膜,所得可食膜的综合性能较优,其水溶性为35.8%,断裂伸长率为75.4%,拉伸强度为10.58 MPa,弹性模量为13.47 MPa。结论随着酪蛋白酸钠含量的增加,膜的水溶性变化不大,膜的断裂伸长率先增大后减小,拉伸强度和弹性模量均随之增大;随着壳聚糖含量的增加,膜的水溶性逐渐下降,膜的断裂伸长率、拉伸强度、弹性模量均随之增大;随着甘油含量的增加,膜的水溶性逐渐减小,膜的断裂伸长率逐渐增大,拉伸强度和弹性模量逐渐减小。     

Preparation and characterisation of PE films of carbon nanotube/polyaniline (PAN) composite mixture

ABSTRACT

Polyaniline (PAN) composites filled with nanotube were prepared by twin-screw extruder in order to study the influence of PE reinforcing effect on the mechanical behaviour of the nanotube/polyaniline (PAN) composites. The mechanical property tests of the composites with and without PE were performed. The tensile and flexural strength of nanotube/polyaniline (PAN) composites with polyethylene (PE) was improved. In conclusion, the addition of PE favoured the improvement of the higher interface strength and so had good effect on improving the tensile and flexural properties of the composites. The dielectric strength was slightly increased with the PE content increasing and then decreased gradually. The hybrid film with 2 wt.% of PE shows the dielectric strength of 199 MV/m, which is about 6% higher than that of nanotube/polyaniline (PAN) film (188 MV/m).     

Comparison of the influence of copper micro- and nano-particles on the mechanical properties of polyethylene/copper composites

This article reports on the influence of copper content and particle size on the tensile properties of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE) mixed with up to 25 vol.% Cu micro-particles and up to 5 vol.% Cu nano-particles, and on the influence of Cu micro-particle content on the dynamic mechanical properties of these polymers. This influence depends upon the extent of branching and crystallinity in the particular polymer. The copper micro-particles seemed to have a negligible influence on the tensile strength of LDPE and HDPE, while there was quite a significant reduction in tensile strength when LLDPE was used as matrix. The elongation at break generally decreased with increasing copper content, but the effect was more significant in the case of LDPE and HDPE. The tensile modulus generally increased with increasing Cu content, but the extent of increase was lower in the case of the more crystalline HDPE. The nano-copper containing samples showed comparable properties at equivalent Cu contents. The storage and loss moduli generally increased with increasing Cu. For all three polyethylenes the β-transition (where present) was not significantly influenced by the presence and amount of copper, but the α-transition was strongly influenced, especially in the case of LDPE and LLDPE.     

硅藻土添加对HDPE/LDPE基抗氧化活性膜性能的影响

目的研究硅藻土添加量对HDPE/LDPE基抗氧化活性膜的拉伸强度、阻氧阻湿性能、热封性能等物理性能及抗氧化剂在活性膜中释放性能的影响。方法以硅藻土为活性膜内层的无机填料,乙烯-醋酸乙烯共聚物(EVA)为无机填料增容剂,槲皮素为抗氧化剂,采用共挤流延法制备外层为HDPE、内层为LDPE的HDPE/LDPE基多层抗氧化活性膜,通过改变内层膜中硅藻土的添加量调整槲皮素从活性膜中的释放。结果添加硅藻土的质量分数为0,1%,2%,3%,4%时,槲皮素扩散系数D(cm2/s)分别为5.91×10-13,2.30×10-11,1.59×10-11,2.44×10-11,3.22×10-11。随着硅藻土的增加,活性膜的热封强度逐渐减小,拉伸强度先增加后减小,透氧系数、透湿系数均呈先减小后增加的趋势。结论硅藻土的添加对活性膜的拉伸性能、阻氧阻湿性能影响较小,显著削弱了活性膜的热封性能,使达到平衡时槲皮素的最终释放量增加;硅藻土的添加及添加量的改变能有效调整槲皮素的释放。     

胶原蛋白/低密度聚乙烯复合材料的制备与性能

为了探讨胶原蛋白（HC）和相容剂马来酸酐接枝低密度聚乙烯（LDPE-g-MAH）对聚合物材料性能产生的影响,以低密度聚乙烯（LDPE）为基体,用共混挤出的方法制备了HC/LDPE复合材料和HC/LDPE-MAH复合材料,并将复合材料注塑成不同规格样条。通过力学性能测试、SEM和热分析等表征方法研究了HC和LDPE-g-MAH含量对HC/LDPE及HC/LDPE-MAH复合材料结构和性能的影响。结果表明：当HC加入量为5wt%时,HC/LDPE复合材料拉伸强度达到最大值15.824 MPa;LDPE-g-MAH的加入可明显改善界面粘结性,提高材料力学性能及热稳定性,当HC含量为20wt%,LDPE-g-MAH含量为4wt%时,HC/LDPE-MAH复合材料的拉伸性能最优。     

Electron beam irradiation enhanced of Hibiscus cannabinus fiber strengthen polylactic acid composites

This paper reported the effects of increasing Hibiscus cannabinus fiber (also known as kenaf fiber) loading level on properties of electron beam irradiated polylactic acid/low density polyethylene (PLA/LDPE). PLA and LDPE were compounded with 5–20 parts per hundred resins (phr) of kenaf respectively to enhance mechanical properties. The compounded kenaf added PLA/LDPE samples were electron beam irradiated from 15 to 60 kGy. The physical properties of kenaf added PLA/LDPE samples were characterized using gel content, X-Ray diffraction and scanning electron microscopy analysis. The results showed that the increasing of irradiation dosages in PLA/LDPE have gradually increased the gel content and tensile strength due to the formation of crosslinking networks in polymer matrix. However, the higher loading level of kenaf and irradiation dosages could decrease the elongation at break of PLA/LDPE samples. This is due to the restriction of polymer chains mobility as resulted by the poor interfacial adhesion between polymer matrix and kenaf particles as well as the formation of crosslinking networks in polymer matrix limits the sliding of polymer chains. Meanwhile, the increasing of kenaf loading level also has gradually increased the crystallinity of PLA/LDPE matrix. It is concluded that the electron beam irradiation dosages and amount of kenaf fiber in PLA/LDPE matrix should be kept at maximum 45 kGy and 15 phr, respectively for better combination to enhance the properties of the composites.