泡沫塑料主要力学性能及其力学模型

描述发泡塑料力学性能的模型,讨论了普通发泡塑料的力学性能以及它和发泡塑料密度的关系。并且比较了硬质聚氨酯(RPUR)和聚氯乙烯(PVC)泡沫塑料的主要力学性能随密度的变化。最后介绍了微孔发泡塑料的几项优良的力学性能。     

竹粉/PVC发泡复合材料的制备与性能研究

采用模压法制备了竹粉/聚氯乙烯(PVC)发泡复合材料,研究了邻苯二甲酸二辛酯(DOP)、发泡剂偶氮二甲酰胺(AC)、竹粉、成核剂及成型压力对复合材料密度和力学性能的影响。结果表明:添加DOP使复合材料密度和拉伸强度下降,断裂伸长率快速增大;AC发泡剂用量增加,复合材料密度减小;竹粉用量增加,复合材料密度增加,力学性能变差;纳米二氧化钛和轻质碳酸钙的添加能有效改善复合材料的性能,其最佳用量为2份;复合材料最佳成型压力为6 MPa。     

聚丙烯/木粉复合材料的制备及其力学性能的研究

以聚丙烯为基体,木粉为填料,采用机械共混、二次挤出共混和注塑成型方法制备不同木粉含量的PP/木粉复合材料,并且测定了PP/木粉复合材料的力学性能。实验结果表明:随着木粉用量的增加,复合材料拉伸强度逐渐增大;木粉用量为60%时,复合材料拉伸强度达到最大值36.04 MPa;木粉用量为80%时,复合材料拉伸强度降低到34.60 MPa。木粉的含量由20%增加到80%,复合材料弹性模量由579.12 MPa增加到869.80MPa,断裂伸长率从18.92%降低到7.39%,冲击强度由9.33 kJ/m2降低到7.76 kJ/m2。这是因为PP/木粉复合材料体系中随着木粉含量的增加,木粉起到了应力集中的作用,使材料变脆,冲击强度降低。     

Study on the Mechanical and Thermal Properties of Jute-Reinforced Methyl Acrylate Grafted PET Composites

Polyethylene terephthalate (PET) granules were grafted with methyl acrylate (MA) from the solution containing 10% MA in methanol (86%) solvent and photo initiator (4%) for 10 min and then cured under UV radiation. MA-grafted PET films were prepared at 260°C and 5 ton pressure using heat press. Jute fabric-reinforced, MA-grafted, PET-based composites (25% fiber by weight) were fabricated by compression molding. Mechanical, thermal and soil degradation tests of the composites were performed. It was found that the MA grafted PET composites showed higher mechanical properties over the ungrafted PET/jute composite.     

Preparation and Mechanical Properties of Polyamide-6 Composites Reinforced with Fir Flour/SiO2 Hybrid Material

Fir flour/SiO₂ hybrid material (FSHM) was fabricated by Sol-gel infiltration process. The morphology and structure were investigated by Fourier transformed infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The composites of polyamide-6 (PA6) reinforced with FSHM were prepared by melt-mixing in twin-screw extruder. Part of FSHM was treated with γ-aminopropyltriethyoxysilane or epoxy resin as compatibilizer. Tensile strength of the composites with 25 wt.% of FSHM increased by almost 23.3% compared to that of pure PA6, whereas 59.8% increase in flexural strength was observed. Both compatibilizers improved interfacial adhesion between FSHM and PA6, resulting in increased impact strength of the composites.     

Mechanical,Thermal and Morphological Properties of Grewia Optiva Fiber/Polymer Matrix Composites

This work is concerned with the evaluation of properties of compression molded Grewia Optiva fiber reinforced Resorcinol-Formaldehyde (RF) matrix-based polymer composites. Reinforcing of the RF resin with Grewia Optiva fiber was done in the form of particle size (200 micron). Present work reveals that mechanical properties such as: tensile strength, compressive strength, flexural strength and wear resistance of the RF matrix have been found to increase up to 30% fibre loading (in terms of weight) and then decreases for higher loading. Morphological and thermal studies of the matrix, fibre and particle reinforced (P-Rnf) green composites have also been studied.     

木粉/聚丙烯复合材料力学性能及结晶行为研究

研究了木粉/聚丙烯复合材料的力学性能,结晶行为和微观结构.在木粉含量很高的情况下材料保持很好的拉伸强度,而材料的韧性随着木粉含量的增加下降很大.增容剂MA-PP的加入对材料的拉伸强度很很大的提高,而对冲击强度的影响不大.木粉/PP复合材料的结晶温度随着木粉含量的增加而增大,表明木粉对PP有异相成核的作用.复合材料电镜照片显示木粉在树脂中即使在较高含量下也分散均匀,马来酸改性聚丙烯(MA-PP)的加入提高木粉与树脂基体的界面结合.     

Mechanical and Thermal Performances of Roselle Fiber-Reinforced Thermoplastic Polyurethane Composites

The aim of this paper is to present research findings on the measurements of mechanical, morphological, and thermal properties of Roselle fiber-reinforced thermoplastic polyurethane composites. The Roselle fiber/thermoplastic polyurethane composites were prepared with fibers of different sizes such as 125?µm and lower, 125–300 and 300–425?µm by internal mixer and hot press at 170°C. The results show that mechanical properties (tensile, flexural, and impact properties) of the composites were improved with the increase in fiber sizes. The highest tensile (10.45?MPa), flexural strength (6.93?MPa), and impact strength (20.22 kJ/m²) was obtained from composites with 300–425?µm fiber size of Roselle fiber/thermoplastic polyurethane composites. Morphological properties of dispersion fiber and tensile fracture surfaces were studied using scanning electron microscope. Thermal properties of the composites were studied using thermogravimetric analyses and results showed that the thermal decomposition effect was almost similar for all compositions.     

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.     

Influence of Nanogels on Mechanical, Dynamic Mechanical, and Thermal Properties of Elastomers

Use of sulfur crosslinked nanogels to improve various properties of virgin elastomers was investigated for the first time. Natural rubber (NR) and styrene butadiene rubber (SBR) nanogels were prepared by prevulcanization of the respective rubber lattices. These nanogels were characterized by dynamic light scattering, atomic force microscopy (AFM), solvent swelling, mechanical, and dynamic mechanical property measurements. Intermixing of gel and matrix at various ratios was carried out. Addition of NR gels greatly improved the green strength of SBR, whereas presence of SBR nanogels induced greater thermal stability in NR. For example, addition of 16 phr of NR gel increased the maximum tensile stress value of neat SBR by more than 48%. Noticeable increase in glass transition temperature of the gel filled systems was also observed. Morphology of these gel filled elastomers was studied by a combination of energy dispersive X-ray mapping, transmission electron microscopy, and AFM techniques. Particulate filler composite reinforcement models were used to understand the reinforcement mechanism of these nanogels. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

微发泡PP/GF复合材料力学性能研究

采用化学发泡注塑成型的方法制备了微发泡聚丙烯/玻璃纤维(PP/GF)复合材料;结合成核理论和玻纤增强机理,研究了发泡质量对微发泡PP/GF复合材料力学性能的影响。结果表明:在PP/GF复合材料中添加5.0%纳米SiO2后,纳米SiO2对PP与GF的相容性并无太大影响,微孔发泡PP/GF复合材料的拉伸强度和冲击强度得到较大提高。     

The Mechanical Properties of Wood Fiber-reinforced Polymethylmethacrylate

Abstract

The mechanical properties, e.g. tensile modulus (at 0.1% strain), tensile strength at maximum point and corresponding elongation and breaking energy, as well as impact strength, of compression molded PMMA and PMMA filled with wood fibers (10%-40% by weight of composite) have been investigated. Optimization of molding conditions, (e.g. temperature, time, pressure and mixing aids) was carried out. In optimum conditions of mixing and molding, the effect of different parameters, (e.g. nature and concentration of coupling agents (isocyanates), coating treatment, nature of wood species in the form of various pulps) on the mechanical properties of the resulting composites were evaluated. PMPPIC having 2%-4% (by weight of polymer) was found to behave as a true coupling agent because modulus as well as the tensile and impact strengths were improved. Moreover, PMPPIC acted as a coupling agent even when it was used for treatment of PMMA and fiber or to precoat the fiber. A distinct effect of the morphology of wood species and fiber-making techniques on the mechanical properties of wood fiber-filled composites was also observed.     

三维编织复合材料的细观结构与力学性能

归纳、梳理了三维编织复合材料细观结构表征方面较有代表性的单胞模型,分析、比较各结构模型的优缺点,从理论分析与试验测试两方面总结三维编织复合材料刚度和强度性能的研究成果与进展,探讨了细观结构表征与力学性能预报中存在的主要问题,并展望今后的研究重点与发展方向。     

棉皮纤维增强聚丁二酸丁二醇酯复合材料的热性能及力学性能研究

采用连续式蒸汽爆破法对棉皮纤维进行预处理,将其与聚丁二酸丁二醇酯(PBS)进行共混,制备了PBS/棉皮纤维复合材料。利用扫描电镜对棉皮纤维及PBS/棉皮纤维复合材料的微观形貌进行了分析,并研究了棉皮纤维含量对PBS/棉皮纤维复合材料熔融及结晶行为、热降解性能、热变形温度以及力学性能的影响。结果表明:经蒸汽爆破处理后,棉皮纤维直径变小,比表面积变大,在PBS基体中分散均匀;棉皮纤维的存在改变了PBS的熔融峰值温度,提高了其结晶度;与纯PBS相比,PBS/棉皮纤维复合材料在高温条件下的热稳定性得到改善维,卡软化温度和弯曲强度提高。     

稻壳粉/PP复合材料性能的研究

分别将未处理和经过表面处理的稻壳粉填充到聚丙烯(PP)中,制备了稻壳粉/PP填充复合材料。探讨了稻壳粉改性及其含量对该复合材料性能的影响。结果表明:当稻壳粉含量为40 phr时,稻壳粉/PP复合材料的综合性能较好;另外,相对于未经表面改性处理的稻壳粉,改性稻壳粉的PP填充复合材料的力学性能、热性能、流动性能均有不同程度的提高。     

Electrical and Mechanical Properties of Thermoplastic Polyurethane and Polytetrafluoroethylene Powder Composites

To determine the possibility of using polytetrafluoroethylene (PTFE) powder as reinforcing filler in the thermoplastic matrix, the thermoplastic polyurethane (TPU) as the matrix and PTFE powder as reinforcing filler were used to prepare a particulate reinforced composite, in order to determine testing data for electrical and mechanical properties of the composites according to the filler loading in respect to TPU polymer matrix. The TPU and PTFE powder composites were prepared by the milling TPU with 2.5, 5, 7.5, and 10 wt% of PTFE powder in a two roll mill and the milled material is compression moulded to make sheets. From the sheets, the test specimens were made and tested for electrical properties—dielectric strength, dielectric constant, surface, and volume resistivity; fire resistance—rate of burning; mechanical properties—tensile strength and elongation, impact strength, hardness; density and melt flow index. The incorporation of PTFE powder has significantly improved the electrical properties—dielectric strength, dielectric constant, surface and volume resistivity; and fire resistance—rate of burning of thermoplastic polyurethane. However, the tensile strength decreased from 24.91 to 14.71 MPa and tensile elongation increased from 620 to 772 percentage.     

木粉填充PP的力学性能

用松木粉／杉木粉对聚丙烯填充改性的实验研究对象,探讨了木粉的种类,表面处理和填充量对ＰＰ力学性能的影响。     

纤维素纳米纤丝/聚乙烯醇复合材料热性能与力学性能研究

通过溶液浇铸法制备了纤维素纳米纤丝(CNFs)/聚乙烯醇(PVA)复合材料,利用TG、DSC、DMA等方法考察了CNFs对PVA热性能与力学性能的影响。结果表明:CNFs的加入提高了PVA的结晶度与熔点,但随着CNFs含量的增加,由于CNFs与PVA之间存在较强的氢键作用,限制了PVA分子链的运动,使得PVA的熔点与结晶度略有下降;CNFs的加入使得PVA的玻璃化转变温度、拉伸强度与弹性模量提高,添加2%CNFs的PVA复合材料的拉伸强度与弹性模量均达到最大值,分别较纯PVA提升了28.9%与14.1%。     

Thermal,Mechanical and Morphological Characterization of Jute/Gelatin Composites

Jute fabrics/gelatin biocomposites were fabricated using compression molding. The fiber content in the composite varied from 20–60 wt%. Composites were subjected to mechanical, thermal, water uptake and scanning electron microscopic (SEM) analysis. Composite contained 50 wt% jute showed the best mechanical properties. Tensile strength, tensile modulus, bending strength, bending modulus and impact strength of the 50% jute content composites were found to be 85 MPa, 1.25 GPa, 140 MPa and 9 GPa and 9.5 kJ/m², respectively. Water uptake properties at room temperature were evaluated and found that the composites had lower water uptake compared to virgin matrix.     

Electrical and Mechanical Properties of Some Composites with Polymeric Matrix

Abstract

The present study aims to investigate the dielectric properties as well as the mechanical properties of polymethyl methacrylate-carbon black and polyester-carbon black composites using semi-reinforcing furnace (SRF) and high abrasion furnace (HAF) carbon blacks.

The permittivity ε' was found to increase by increasing carbon black content and showed anomalous dispersion. The absorption spectra (ε'' vs. frequency) from 100 Hz to 10 MHz were analyzed using a computer program based on Fröhlich terms. Four absorption regions were obtained for either the polymer matrix or loaded samples.

The first region in the lower frequency range could be attributed to Maxwell-Wagner effect resulting from the differences in the conductivities of the ingredients of the composite. The second and third regions in the higher frequency range could be attributed to the large and small aggregates caused by movements of the main chain. The fourth region may occur due to segmental rotation (ester group or carbonyl group) or local twisting motion of the main chain. At higher carbon black concentration, the relaxation time for different regions except that for Maxwell-Wagner effect became higher and carbon black seems to interact with the polymer matrix giving rise to large aggregates resulting high relaxation times.

The mechanical properties for the investigated samples were also examined, the results showed that the tensile strength is higher in the case of smaller particle size carbon black HAF. This could be attributed to a good incorporation of carbon black of small particle size into the polymer matrix. Also, the morphology study indicates the presence of aggregates and some arrangements on adding carbon black.