Studies of the Physico-Mechanical,Interfacial, and Degradation Properties of Jute Fabrics/Melamine Composites

Jute fabrics/melamine composites (20% fiber) were prepared by compression molding. Mechanical properties of the composites were evaluated. Mechanical properties of starch-treated jute/melamine composites, including tensile strength (31%), bending strength (29%), tensile modulus (23%), bending modulus (25%), impact strength (113%), and hardness (4%), inproved significantly over the untreated composite. Fracture surfaces of untreated and treated composites were studied by scanning electron microscopy (SEM) and supported poorer fiber matrix adhesion for the untreated composite than that of the treated composite. Water uptake and soil degradation tests of untreated and treated composites were also performed.     

Improvement of Mechanical Properties of Jute Fibers-Polyethylene/Polypropylene Composites: Effect of Green Dye and UV Radiation

Jute-reinforced polyethylene (PE), polypropylene (PP) and mixture of PP/PE composites were prepared. It was found that 90% PP and 10% PE matrices based jute reinforced composites performed the better results. UV radiation at different intensities was applied both on matrices and jute. Mechanical properties of the irradiated jute- and matrices-based composites were found to increase significantly. Optimized jute fabrics were also treated with different concentrations of green dye (0.1–1%, w/w) with 2% K₂O₈S₂ in methanol solution for 2–8 min. A composite made of 0.5% green dye jute (5 min soaking time) and irradiated matrix showed the best mechanical properties.     

Effects of Surface Pretreatment on the Mechanical and Dielectric Properties of Photocuring Jute Fibers

Jute fabrics were treated with ethylene glycol dimethylacrylate (EGDMA) + MeOH solutions at different proportions along with photoinitiator Irgacure 907 and cured under UV-radiation. Monomer concentration, soaking time, and radiation dose were optimized in terms of polymer loading and mechanical properties. Twenty-five percent EGDMA, 30-minute soaking time, and tenth-pass of radiation produced higher tensile strength (75%) and tensile modulus (88%) than those of the untreated sample, as well as the highest polymer loading value (70%). Among different additives used, urea showed the best performance. SEM, water uptake, and dielectric properties of the samples were studied.     

A Comparative Study on the Mechanical,Degradation and Interfacial Properties of Jute/LLDPE and Jute/Natural Rubber Composites

Jute fabric (hessian cloth) reinforced low-density polyethylene (LLDPE) composites (40 wt%) and solid natural rubber-(NR) based composites (40 wt%) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM) and percentage elongation at break (Eb) of jute/LLDPE composites were found to be 29, 680 MPa and 20%, and for jute/NR-based composites were also found to be 15, 122 MPa and 94%, respectively. Interfacial shear strength (IFSS) of the jute/LLDPE and jute/NR systems was investigated by using the single fiber fragmentation test (SFFT). Scanning electron microscopy (SEM) and aqueous degradation tests were also performed.     

Effect of Ultraviolet Radiation and Potassium Permanganate on the Physico-Mechanical Properties of Jute Polymer Composites

Jute fabrics-reinforced polymer composites were prepared with different formulations using oligomer (M-1200), methanol and benzoyl peroxide. Fiber content in the composites was optimized and 55% jute content at oligomer: methanol: benzyl peroxide = 75:24.5:0.5 (w/w) ratios showed better mechanical properties. Jute fabrics were treated with potassium permanganate (KMnO₄) solution of different concentrations for different soaking times. Optimized jute fabrics were soaked in the optimized formulation (F3) and cured under UV radiation at different intensities and measured their mechanical properties. Scanning electron microscopy (SEM), water uptake and soil degradation test of the treated and untreated composite samples were performed.     

Effect of Ultraviolet Radiation on the Mechanical and Dielectric Properties of Hessian Cloth/PP Composites with Starch

Hessian cloth (jute fabrics) reinforced poly(propylene) (PP) composites (45 wt% fiber) were prepared by compression molding and the mechanical properties were evaluated. Jute fabrics and PP sheets were treated with UV radiation at different intensities and then composites were fabricated. It was found that mechanical properties of the irradiated jute and irradiated PP-based composites were found to increase significantly compared to that of the untreated counterparts. Irradiated jute fabrics were also treated with aqueous starch solution (1–5%, w/w) for 2–10 min. Composites made of 3% starch-treated jute fabrics (5 min soaking time) and irradiated PP showed the best mechanical properties. Tensile strength, bending strength, tensile modulus, bending modulus and impact strength of the composites were found to improve 31, 41, 42, 46 and 84% higher over untreated composites. Water uptake, thermal degradation and dielectric properties of the resulting composites were also performed.     

汽车内饰用PP/黄麻纤维复合材料力学性能

采用转矩流变仪混合造粒,通过注射成型方法制备了聚丙烯(PP)/黄麻纤维复合材料,研究了对纤维表面进行处理的NaOH浓度、纤维含量和相容剂的含量对PP/黄麻纤维复合材料力学性能的影响,采用扫描电镜对纤维表面及复合材料的断面形貌进行分析。结果表明:黄麻纤维经过碱处理后PP/黄麻纤维复合材料的力学性能优于纤维未处理的复合材料的力学性能,随着NaOH浓度的提高,PP/黄麻纤维复合材料的拉伸强度和冲击强度增加,在NaOH浓度为16%时,其拉伸强度和冲击强度最佳;其弯曲强度随着NaOH浓度的提高先增加而后下降,在8%浓度时,弯曲强度最大。随着纤维含量的提高,PP/黄麻纤维复合材料的拉伸强度和弯曲强度先增加后下降,在纤维含量达到20%时,PP/黄麻纤维合材料的拉伸强度和弯曲强度达到最大。随着纤维含量的提高,PP/黄麻纤维复合材料的冲击强度降低。相容剂的加入使得PP/黄麻纤维复合材料的拉伸强度和弯曲强度明显增加。     

Fabrication and Mechanical Characterization of Jute Fabrics: Reinforced Polyvinyl Chloride/Polypropylene Hybrid Composites

Jute fabrics such as reinforced polyvinyl chloride (PVC), polypropylene (PP), and a mixture of PVC and PP matrices-based composites (50 wt% fiber) were prepared by compression molding. Tensile strength (TS), bending strength (BS), tensile modulus (TM), and vbending modulus (BM) of jute fabrics' reinforced PVC composite (50 wt% fiber) were found to be 45 MPa, 52 MPa, 0.8 GPa, and 1.1 GPa, respectively. The effect of incorporation of PP on the mechanical properties of jute fabrics' reinforced PVC composites was studied. It was found that the mixture of 60% PP and 40% PVC matrices based composite showed the best performance. TS, BS, TM, and BM for this composite were found to be 65 MPa, 70 MPa, 1.42 GPa, and 1.8 GPa, respectively. Degradation tests of the composites for up to six months were performed in a soil medium. Thermo-mechanical properties of the composites were also studied.     

Surface Modification of Jute Fabrics Using Acrylic Monomers: Effect of Additives

Jute fabrics were modified with methyl acrylate (MA), ethyl acrylate (EA), and 2-hydroxyethyl acrylate (2-HEA) using UV radiation at different periods of time. It was found that 30% MA at 60 min, 15% EA at 40 min, and 15% 2-HEA at 15 min irradiation time in methanol along with photoinitiator showed the best results. Some additives, such as urea, acrylamide (AM), ethylhexyl acrylate (EHA), tripropelene glycol diacrylate (TPGDA), and trimethylol propane triacrylate (TMPTA), were incorporated into the optimized monomer solutions and monitored its effect on the properties. Various physico-mechanical properties of both treated and untreated jute fabrics were also performed.     

Comparative Studies on the Mechanical,Degradation and Interfacial Properties between Jute and E-Glass Fiber-Reinforced PET Composites

Jute fiber mat (hessian cloth) reinforced PET-based composites (50% fiber by weight) and E-glass fiber matreinforced PET based composites (50% fiber by weight) were fabricated by compression molding and the mechanical properties tensile strength (TS), tensile modulus (TM), elongation at break (%), bending strength (BS), bending modulus (BM), impact strength (IS) and hardness (Shore-A) of the composites were evaluated and compared. The interfacial properties of the both composites were also compared. Water uptake test and soil degradation test were also investigated.     

Mechanical and Electrical Properties of Jute Fabrics Reinforced Polyethylene/Polypropylene Composites: Role of Gamma Radiation

Jute fabrics reinforced polyethylene (PE), polypropylene (PP) and mixture of PP+PE matrices based composites (50 wt% fiber) were prepared by compression molding. It was found that the mixture of 80% PP + 20% PE hybrid matrices based jute fabrics reinforced composites performed the best results. Gamma radiation (250–1000 krad) was applied on PP, PE and jute fabrics then composites were fabricated. The mechanical properties of the irradiated composites (500 krad) were found to increase significantly compared to that of the non irradiated composites. Electrical properties like dielectric constant, loss tangent and conductivity with temperature variation of the composites were studied.     

MWCNTs/PP多层复合膜的结构及介电性能

将不同含量多壁碳纳米管(MWCNTs)的聚丙烯(PP)薄膜,通过热压叠层复合的方法制备了MWCNTs/PP多层复合膜。利用扫描电子显微镜(SEM)和电感电容电阻测试仪(LCR)研究了MWCNTs含量和多层结构对MWCNTs/PP多层复合膜介电性能的影响。结果表明:随着MWCNTs含量和复合层数的增加,低频下介电常数得到明显提高,介电损耗增加趋缓。结合微结构的表征结果,建立了微结构-介电性能之间的关系,导电层和绝缘层的交替结构使得MWCNTs/PP多层复合膜的介电常数显著提高,介电损耗仅有微小增加。     

偶联剂对黄麻增强聚丙烯复合材料冲击强度的影响研究

文章采用塑炼机熔融共混的方法制备了黄麻纤维增强聚丙烯复合材料,用马来酸酐接枝聚丙烯作为偶联剂,制备出性能较好的聚丙烯复合材料。通过力学测试研究了复合材料的抗冲击性能。     

柠檬石膏/聚丙烯复合材料的制备与性能

研究了柠檬石膏及表面处理柠檬石膏对聚丙烯(PP)复合材料的力学性能、微观形貌、结晶度、熔点的影响。结果表明:柠檬石膏的加入使复合材料的拉伸强度、弯曲强度和弯曲模量有不同程度提高,用钛酸酯和铝酸酯偶联剂对柠檬石膏进行表面处理后效果较好。扫描电镜(SEM)分析结果显示经过偶联剂表面处理的柠檬石膏在PP中分散的较未处理的柠檬石膏均匀。差示扫描量热(DSC)结果表明:柠檬石膏的加入在提高PP的结晶度同时,对复合材料的熔点几乎没有影响;相比未表面处理的柠檬石膏,表面处理后的柠檬石膏对复合材料中PP的结晶度和熔点均没有显著影响。     

热压条件对短切SiCf/LAS复合材料介电/力学性能的影响

采用热压烧结法制备出致密度超过90%的短切SiCf增强LAS玻璃陶瓷基复合材料,讨论了热压温度与压力对复合材料性能的影响。力学测试表明,当热压温度由1200℃上升到1280℃,复合材料断裂强度从124MPa下降到80MPa,断裂韧性从3.27MPa.m1/2下降到2.92MPa.m1/2;当热压压力由20MPa提高到34MPa,复合材料断裂强度从124MPa下降到86MPa,断裂韧性从3.27MPa.m1/2下降到3.00MPa.m1/2。断口形貌SEM观察结果表明,因纤维掺入过量,φ(SiCf)=36%,使纤维与基体结合较差;而过高的热压温度与压力会使界面反应加剧,破坏纤维强度及纤维与基体的结合。介电性能测试表明,在8～12GHz频率,复合材料复介电常数的实部ε′由基体的7.6增大到10～70,虚部ε″由基体的0.34增大到60～160,介电损耗tgδ由基体的0.04增大到2～20,并具有明显的频散效应。而且,随热压温度升高或者热压压力的增加,复合材料ε′增大,而ε″与tgδ减小。复合材料具有成为电损耗型宽带微波吸收材料的潜力。     

聚丙烯/铜金粉复合材料的制备及其性能分析

将硅烷偶联剂K570、液体石蜡、聚丙烯(PP)、铜金粉通过螺杆挤出机共混造粒,并通过注塑机制备不同铜金粉含量的哑铃形样条。利用差示扫描量热仪、场发射扫描电子显微镜、万能强力机、介电常数仪对样条热性能、形貌结构、力学性能和介电性能等进行分析。结果表明,随着铜金粉含量的增加,结晶度、拉伸强度和断裂伸长率均呈先增大后减小的趋势;铜金粉含量为1.5 %（质量分数,下同）时,断裂强度达到最大为49.98 MPa;当铜金粉含量为2 %时,断裂伸长率最高为426.3 %;在3.1×108~4.1×108 Hz的超短波频率范围内,铜金粉含量为2 %时,样条的介电常数实部最高。     

Preparation,Characterization, and Dielectric Properties of PP/CaTiO3 Composites for Microwave Substrate Applications

Calcium titanate (CaTiO₃) filled polypropylene (PP) composites have been fabricated through compression molding method. The phase purity of the PP/CaTiO₃ composites was studied using X‐ray diffraction studies. Scanning electron microscopy technique has been employed to study the dispersion of the particulate filler in the PP matrix. The dielectric constant and loss tangent of the composites were measured at X‐band frequency region using waveguide cavity perturbation technique. PP/CaTiO₃ composite has an effective dielectric constant of 11.74 and loss tangent 0.007 at optimum filler loading. The experimental dielectric constant of filled composites was compared with theoretically predicted dielectric constant values obtained using different modeling approaches. The linear coefficient of thermal expansion of PP/CaTiO₃ composites was studied using thermomechanical analyzer.     

PP-MAH对PP/汉麻纤维复合材料结构及性能的影响

研究了PP-MAH对注射成型PP/汉麻纤维(HFs)复合材料的皮－芯层形态结构及力学性能的影响。结果表明,未添加PP-MAH的复合材料体系中,HFs在注塑试样皮层和芯层沿流动方向高度取向。在试样皮层,HFs诱导PP产生 晶。试样皮层呈现韧性断裂行为,而芯层则发生脆性断裂;添加5份（质量份数,下同）PP-MAH后,HFs在注塑试样皮层高度取向,然而在试样芯层HFs呈现无规则分布。与未添加PP-MAH的体系相比,试样皮层中,HFs诱导PP产生 晶能力减弱,复合材料的冲击强度稍有降低,且皮层和芯层试样均呈脆性断裂行为。添加PP-MAH的复合体系拉伸强度和弯曲强度则呈明显提高趋势。     

加工方式对PP/EAA/LDH复合材料性能影响

进行了聚丙烯(PP)、乙烯–丙烯酸共聚物(EAA)及水滑石(LDH)复合材料改性一体化研究,并研究了一次熔融挤出加工法和二次熔融挤出加工法对PP复合材料性能的影响。X射线多晶衍射、透射电子显微镜分析表明:两种加工方法制备的复合材料中EAA均插层和剥离了LDH,改善了LDH在PP基体中分散性,并且一次挤出加工效果优于二次挤出加工效果;热失重分析表明,两种加工方式均提高了复合材料的热稳定性能;静态力学性能测试表明:一次挤出加工制备的复合材料PP1的拉伸强度、拉伸弹性模量和缺口冲击强度均高于二次挤出加工制备的复合材料PP2。实验表明一次熔融挤出加工方法对复合材料中LDH插层和剥离效果以及LDH在PP基体中分散效果优于二次熔融挤出加工。     

Effect of Sodium Bicarbonate on the Mechanical and Degradation Properties of Short Jute Fiber Reinforced Polypropylene Composite by Extrusion Technique

Short jute fibers and the pellets of polypropylene (PP) were compounded to make composites with the help of an extruder followed by compression molding. The mechanical properties of the composites increased with the increase of fiber content up to 20%, then decreased while the jute content varied from 5 to 30 wt%. Composites with varying percentages (5 to 20%) of sodium bi-carbonate at constant (20%) jute content were made by same process. The mechanical properties, soil degradation tests, and the water uptake capacity of the composites were investigated properly. Also, the density of the composite was reduced up to 21.54%.