石墨烯添加量对铜基复合材料性能的影响

采用一步化学还原法结合放电等离子烧结工艺制备石墨烯增强铜基复合材料,利用XRD、SEM、拉曼光谱、拉伸试验机、纳米压痕仪、涡流电导率仪等研究石墨烯含量对复合材料微观组织、力学性能和导电性能的影响。结果表明:石墨烯在复合材料基体中均匀分布,石墨烯的添加能显著增强铜基体的力学性能。与纯铜相比,添加0.025%(质量分数)的氧化石墨烯,可使其屈服强度提高219.8%,抗拉强度提高35.9%,弹性模量提高6.9%,此外,其导电率仍有93.1%IACS。随着石墨烯含量的增加,复合材料的屈服强度、抗拉强度及弹性模量均有所下降,这是因为高石墨烯含量复合粉体中部分石墨烯纳米片未能被铜颗粒包覆,其与铜基体界面结合强度低,石墨烯的剪切应力转移强化效果降低。     

氧化石墨烯纳米带/TPU复合材料薄膜制备及性能表征

采用氧化法将碳纳米管纵向切割成氧化石墨烯纳米带,利用溶液成形在涂膜机上制备氧化石墨烯纳米带/TPU复合材料薄膜。FT-IR、拉曼光谱、XRD、FE-SEM、TEM等测试表明,碳纳米管成功地被纵向切割成带状结构的氧化石墨烯纳米带。力学测试表明,当氧化石墨烯纳米带用量为2%(质量分数)时,复合材料薄膜弹性模量与拉伸强度相比TPU薄膜提高了160%与123%。氧气透过率测试表明当氧化石墨烯纳米带用量为2%(质量分数)时,复合材料薄膜氧气透过率降低77%,阻隔性能明显提高。     

POE增韧改性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,采用密炼塑化、双辊混炼、模压发泡方法制备高发泡弹性材料。用智能型发泡无转子硫化仪分析POE对LDPE正硫化时间、扭矩值、发泡气体压力的影响,用扫描电镜观察POE与LDPE之间的相结构以及发泡后泡孔孔径的影响,测试了LDPE/POE发泡材料的物理力学性能。结果表明:随着POE含量的增加,其复合材料正硫化时间延长,扭矩值和发泡气体压力增大;POE在LDPE材料中形成"海-岛"结构两相体系;含40质量份POE的LDPE/POE发泡材料孔径均匀性较好,与LDPE发泡材料相比,拉伸强度提高67.2%,断裂伸长率提高82.3%,直角撕裂强度提高25.1%,回弹率提高8%,物理力学性能优良。     

石墨烯/ABS 3D打印复合材料的制备与性能研究

采用气体驱动液相剥离法制备了石墨烯/丙烯腈-丁二烯-苯乙烯共聚物(ABS)3D打印复合材料，测试了材料的力学性能和导电性能。结果表明：石墨烯的添加可以显著地提升3D打印耗材的拉伸强度、弹性模量及导电性；当石墨烯添加质量为4.8%时，复合材料的拉伸强度、弹性模量、最大拉力及电导率达到最大，分别为210MPa、5166MPa、0.4kN及4.46×10^-3S/m。     

苎麻纤维/碳纤维/聚乙烯复合材料的性能研究

将苎麻纤维(RF)、短切碳纤维(SCF)混杂加入低密度聚乙烯(LDPE)树脂中,考察了纤维混杂方式、马来酸酐接枝物添加方式对LDPE/RF/SCF(100/10/5)复合材料力学性能的影响。结果表明:以SCF/LDPE为表层,以RF/LDPE为芯层的夹芯结构LDPE/RF/SCF(100/10/5)复合材料拉伸强度较LDPE/RF(100/15)复合材料提高了49%,冲击强度提高78%;体系中添加3份的马来酸酐接枝物(LDPE-g-MAH)后,复合材料冲击强度提高了8%,马来酸酐接枝物改善复合材料冲击强度比改善拉伸强度更有效。扫描电镜结果表明LDPE-g-MAH能改善麻纤维、碳纤维与基体间的界面结合。     

石墨烯微片对尼龙6的改性研究

采用共混法制备尼龙6/石墨烯微片(GNPs)复合材料,研究了其导电性能、摩擦磨损性能及力学性能,并利用扫描电镜观察分析了材料磨损表面形貌,同时将其结果与炭黑(CB)体系进行了比较。结果表明,PA6/GPNs的渗滤阀值为15%(质量分数,下同),远低于PA6/CB的30%;GNPs的加入降低了材料的摩擦系数和磨损率,并在其含量为10%时达到最佳,分别降低30%和50%;提高了材料的拉伸强度、断裂伸长率、硬度,但冲击强度下降。CB的加入提高了材料的耐磨性、硬度,但摩擦性能、拉伸强度、断裂伸长率和冲击强度均下降。     

单轴拉伸PLLA/PBS共混薄膜的包装特性研究

目的提高聚乳酸(PLLA)的韧性、强度及阻氧性能。方法采用双螺杆挤出流延线制备单轴拉伸PLLA/聚丁二酸丁二醇酯(PLLA/PBS)共混薄膜,用万能拉伸试验机、差示扫描量热分析仪(DSC)和透氧仪,对不同拉伸比例的PLLA/PBS共混薄膜的力学性能、热学性能和阻氧性进行了评估。结果随着拉伸比例的增大,PLLA/PBS共混薄膜屈服强度和弹性模量增大,断裂伸长率呈先增大后降低的趋势。随拉伸比例的增大,PLLA/PBS共混薄膜结晶速率明显提高,其阻氧性也得到一定的改善。结论通过单轴拉伸和与PBS共混提高了PLLA的韧性和强度,中等拉伸比例的PLLA/PBS共混薄膜的阻氧性相对较好。     

石墨烯纳米片改性PBT研究

目的采用石墨烯纳米片对聚对苯二甲酸丁二醇酯(PBT)进行改性,以提高其耐热性能和力学性能。方法采用熔融共混法制备PBT/石墨烯纳米片(MLGN)纳米复合材料,通过DSC、SEM、DMA、耐热性能及力学性能测试,研究石墨烯纳米片对PBT性能的影响。结果石墨烯纳米片具有明显的异相成核效果,显著降低了PBT的结晶活化能,加入质量分数为1%的石墨烯纳米片后,结晶活化能降低了66.2%,加入2%后降低了72.8%;石墨烯纳米片与PBT分子链间具有较强的相互作用,有利于提高PBT的结晶峰值温度、玻璃化转变温度、维卡软化温度和拉伸强度。当MLGN质量分数为2%时,玻璃化转变温度提高了1.7℃,维卡软化温度提高了8.8℃,拉伸强度提高了17%左右。MLGN的质量分数在2%以内对冲击强度没有影响。结论石墨烯纳米片能明显改善PBT的耐热性能和力学性能。     

PEO改性纳米TiO2/LDPE复合薄膜的光降解性能

以聚氧乙烯(PEO)改性纳米TiO2颗粒作为光催化剂,与低密度聚乙烯(LDPE)树脂复合制备了一种新型可光催化降解的TiO2/LDPE纳米复合薄膜,进行了该薄膜在空气中紫外光照下的光催化降解实验。通过表面接触角、失重率、红外光谱(FT-IR)和扫描电镜(SEM)等分析技术系统地研究了该复合薄膜的降解性能。结果表明,PEO的加入能提高薄膜的亲水性和TiO2的分散性,提高TiO2的光催化活性,有利于促进LDPE薄膜的降解。TiO2/PEO/LDPE复合薄膜在0.8mW/cm2紫外光强下照射425h,失重率达到15.2%;在4mW/cm2紫外光强下照射500h,失重率达到38.1%。光照后薄膜的拉伸强度和断裂伸长率显著降低,羰基指数升高。     

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。     

山梨酸-LDPE抗菌薄膜的制备与性能

目的研究山梨酸对低密度聚乙烯(LDPE)薄膜性能的影响。方法将山梨酸粉末添加到低密度聚乙烯树脂中,通过共混、挤出、吹塑等工艺制备出山梨酸-LDPE抗菌薄膜,并研究山梨酸含量对LDPE薄膜的抗张强度、光学性能、水蒸气透过率、微观结构及抗菌性的影响。结果随着山梨酸含量的增加,薄膜的抗张强度先增加再减小,透光率逐渐下降,雾度逐渐上升,薄膜的水蒸气透过系数先下降后上升,山梨酸质量分数在1.5%以上时对大肠杆菌具有抑制作用,在2%以上时对单增李斯特菌和金黄色葡萄球菌具有抑制作用。结论山梨酸-LDPE薄膜具有优良的包装性能和抑菌效果,是一种良好的食品包装材料。     

Studies on the oxygen barrier and mechanical properties of low density polyethylene/organoclay nanocomposite films in the presence of ethylene vinyl acetate copolymer as a new type of compatibilizer

Nanocomposite films based on low density polyethylene (LDPE), containing of 2, 3, and 4 wt.% organoclay (OC) and ethylene vinyl acetate (EVA) copolymer as a new compatibilizer were prepared and characterized using rheological tests, X-ray diffraction, differential scanning calorimetry, oxygen permeation measurements, and tensile tests. There was no exfoliation or intercalation of the clay layers in the absence of EVA, while an obvious increase in d-spacing was observed when the samples were prepared with EVA present. This issue was reflected in the properties of nanocomposites. The oxygen barrier properties of the LDPE/EVA/OC film were significantly better than those of the LDPE/OC film. The average aspect ratio of clay platelets in nanocomposites was determined from permeability measurements and using Lape–Cussler model. In addition to barrier properties, the LDPE/EVA/OC film also had better elastic modulus than their counterparts without EVA. The modulus reinforcement of nanocomposites was studied using Halpin–Tsai equations, which are universally used for composites reinforced by flake-like or rod-like fillers.     

导热聚氨酯弹性体/石墨烯纳米片复合材料的制备及性能

采用液相共混与两次模压方法制备了热塑性聚氨酯弹性体(TPU)/石墨烯纳米片(GN)薄膜,探究了不同GN含量对TPU/GN薄膜力学性能、导热性能和热稳定性的影响。结果表明,当添加质量分数为2.0%GN时,TPU/GN薄膜的拉伸强度和弹性模量分别为60.8 MPa和10.4 MPa,相比纯TPU薄膜分别增长34%和96%; TPU/GN薄膜呈现典型的导热各向异性特征,质量分数为5.0%GN时,薄膜面内方向的导热系数为1.94 W/(m·K),而其垂直方向的导热系数为0.21 W/(m·K);GN的加入提高了TPU的热稳定性。     

Fabrication and Properties of Antioxidant Polyethylene‐based Films Containing Marigold (Tagetes erecta) Extract and Application on Soybean Oil Stability

Four films were extruded in a pilot‐plant scale blown extrusion machine: a monolayer low‐density polyethylene (LDPE) film added with 2.90% of marigold (Tagetes erecta) extract, a two‐layer high‐density polyethylene/LDPE film added with 3.59% of the extract in the LDPE layer and the corresponding two control films without addition of the extract. More than 64% of astaxanthin contained in the extract was lost during the extrusion process. Spectroscopic, optical and mechanical properties of the films were affected by the addition of the marigold extract. The films showed to be light sensitive when exposed to commercial light at 25 °C; however, bags made of the films showed a positive effect on soybean oil stability when used as packaging. Copyright © 2012 John Wiley & Sons, Ltd.     

微纤化纤维素/聚乳酸薄膜的制备及性能分析

目的将微纤化纤维素(MFC)和聚乳酸(PLA)共混成膜,以提高薄膜的透湿、透氧、阻光等性能,满足果蔬等食品的包装要求。方法采用酶解法与机械处理的方法制备MFC,使用硅烷偶联剂KH560对MFC进行疏水改性处理,再将改性处理的微纤化纤维素(MFC-S)与PLA共混制成薄膜。结果当MFC-S的质量分数为0.75%时,MFC-S/PLA共混包装膜的拉伸强度比纯PLA膜增加了13.3%,当MFC-S的质量分数为2%时,MFC-S/PLA共混包装膜的透氧系数为纯PLA膜的1.43倍,透湿系数为纯PLA膜的1.26倍,透光率降低了60%,阻光效果较好。结论 MFC-S的质量分数为0.75%时,包装膜的拉伸强度较好;MFC-S的质量分数为2%时,透氧、透湿、阻光性较好。     

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.     

Development and characterization of PET/Fish Gelatin–nanoclay composite/LDPE laminate

A three‐layer laminate film was developed with the following structure: polyethylene terephthalate (PET)/fish gelatin (FG)–nanoclay composite/low‐density polyethylene (LDPE). The FG–nanoclay composite material functioned as the oxygen barrier layer and demonstrated comparable oxygen barrier properties when compared with a similar laminate utilizing ethylene vinyl alcohol as the barrier layer at a relative humidity (RH) of up to 50%. The introduction of nanometer‐sized filler clay into the FG matrix lowered the oxygen permeability (OP) because of the tortuosity effect of the clay particles. In addition, the FG–nanoclay composite film exhibited bond strengths similar to both LDPE and PET. The hydrophilic nature of FG significantly increases OP under high (>50%) RH conditions. However, this new FG laminate film could be a possible alternative for packaging designers desiring a more sustainable packaging material for low‐RH (<50%) applications. Copyright © 2009 John Wiley & Sons, Ltd.     

增塑剂对马铃薯淀粉基复合膜物理机械性能的影响

以马铃薯淀粉、普鲁兰多糖、明胶为成膜物质,氯化钙为交联剂,甘油、山梨醇、聚乙二醇为增塑剂,采用流延法制备了马铃薯淀粉基复合膜,研究了3种增塑剂对复合膜物理机械性能的影响。结果表明:复合膜的抗拉强度和弹性模量均随增塑剂含量的增加而显著减小,断裂伸长率随甘油和山梨醇含量的增加而显著增加,聚乙二醇对其影响不显著;复合膜的水蒸气透过率和水溶性均随增塑剂含量的增加而增加;聚乙二醇能够显著降低复合膜的透光率。     

Transparent and high gas barrier films based on poly(vinyl alcohol)/graphene oxide composites

Composites of poly(vinyl alcohol) (PVA) and graphene oxide (GO) were synthesized by a modified Hummers method and a solution-mixing method. GO was fully exfoliated in the PVA/GO composites. GO did not affect the crystallization of PVA during solvent evaporation. GO is itself an excellent gas barrier without any chemical reduction. The oxygen permeability of the PVA/GO (0.3 wt.%) composite coated film was 17 times lower than that of the pure poly(ethylene terephthalate) (PET) film, with 92% light transmittance at 550 nm. Composites of PVA and reduced graphene oxide (RGO) were synthesized by performing chemical reduction using hydrazine monohydrate. The oxygen permeability of the PVA/RGO (0.3 wt.%) composite coated film was 86 times lower than that of the pure PET film, with 73% light transmittance at 550 nm. The reduction of oxygen permeability was mainly attributed to the reduced oxygen solubility in the PVA/GO composite film, while it was attributed to both the reduced oxygen diffusivity and solubility in the PVA/RGO composite film.     

蓝藻粉-青霉素菌渣/低密度聚乙烯复合材料配方的响应面法优化设计和验证

为了实现水华蓝藻和青霉素菌渣的资源化利用,并进一步提升蓝藻粉-青霉素菌渣/低密度聚乙烯(LDPE)复合材料的力学性能,以菌渣与蓝藻粉共混物、LDPE为原料,通过响应面法优化实验方案,研究聚乙烯蜡(PE-wax)和白油、马来酸酐接枝聚乙烯(PE-g-MAH)、三乙醇胺对蓝藻粉-青霉素菌渣/LDPE复合材料力学性能的影响。当蓝藻粉-菌渣共混粉末与LDPE的质量比为15.00%和85.00%时,响应面回归方程的方差分析结果表明,PE-g-MAH和三乙醇胺两因素间的交互作用显著,润滑剂与PE-g-MAH、润滑剂与三乙醇胺之间的交互作用不显著;回归方程预测的最佳工艺参数如下:润滑剂、PE-g-MAH、三乙醇胺的质量比分别为3.08%、4.33%和4.23%,此条件下蓝藻粉-青霉素菌渣/LDPE复合材料的拉伸强度、弯曲强度和弯曲模量分别为12.30 MPa、9.03 MPa和220.00 MPa,相较于未添加助剂时的蓝藻粉-青霉素菌渣/LDPE复合材料分别提高了10.81%、29.74%和34.97%。