排序方式: 共有33条查询结果,搜索用时 0 毫秒
1.
N.C. Dafader M.E. Haque F. Akhtar 《高分子科学》2007,(5):519-523
Natural rubber latex(NRL)and methyl methacrylate(MMA)grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties, swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose,and beyond that dose,it becomes almost flat. 相似文献
2.
《Composite Interfaces》2013,20(7-9):605-616
The influence of chemical treatments on the interfacial adhesion of sisal fibres and biodegradable matrices were studied in the present work. For that purpose, four different polymers were used: polycaprolactone (PCL), cellulose acetate, MaterBi Z (a commercial starch/polycaprolactone blend) and MaterBi Y (a commercial starch/cellulose derivatives blend). Alkaline and acetylation treatments were performed on sisal fibres. Properties were determined by means of tensile tests, adhesion measurements and contact angle determination. The interfacial shear strength was correlated with the hydrophilic character of the material. 相似文献
3.
《Composite Interfaces》2013,20(2-3):335-349
In this research the adhesion and the resulting interfacial shear strength (IFFS) between the natural fibres flax, hemp and cotton and the polymer matrices polypropylene with coupling agent (MAPP) and polylactide acid (PLA) was surveyed with the single fibre fragmentation test (SFFT). The adhesion between MAPP and the fibres was good enough to produce fragments, whereas the adhesion between PLA and flax was too weak to transmit enough tension for fibre cracks which is clearly visible on SEM-photographs. Comparing the IFFS values of the fibres in MAPP with an equal fibre diameter shows that the IFFS value of flax is highest with 7.09 N/mm2 followed by hemp 6.13 N/mm2. The IFFS of cotton is a lot smaller (0.664 N/mm2). The critical fragmentation or fragmentation length of the bast fibres flax (3.16 mm) and hemp (3.20 mm) in MAPP is smaller than the critical fragmentation length of cotton (5.03 mm). The adhesion between the lignocellulosic fibres and MAPP is much better than between the lignin and pectin free cellulose fibre and MAPP. Possible reasons for this — the surface structure of the cotton fibre and its different chemical composition being made up of only cellulose, hemi-cellulose and wax with no pectin or lignin present — are discussed. 相似文献
4.
《Composite Interfaces》2013,20(7-9):647-668
This paper aims at introducing a new natural composite used as soil stabilizer with particular application in geotechnical engineering. The fibers introduced in the present study could be used as effective soil reinforcement. This research proves the feasibility of the use of modified jute/polypropylene in lime and cement composites and studies their effects on the tensile and compressive strength of the matrix. In general, the optimal mechanical performance of natural composites and durability depends on the optimization of the interfacial bond between natural fiber and matrix. Since the fibers and matrices are chemically different, strong adhesion at their interfaces is needed for an effective transfer of stress and bond distribution throughout an interface. In this paper a theoretical approach for the identification of elastic modulus in composite interfaces is proposed in detail with a reasonable error. The theoretical approach is based on the method using a sum of least squares criterion. The approach is applied through optimization techniques, using analytical sensitivities and correlating adhesion with Young's modulus. The validity and potentiality of the proposed technique is discussed and the results demonstrated the versatility, accuracy, and efficiency of the presented approach. The applied method also appears to be a simple way of predicting the modulus of elasticity in composite interfaces. This leads to a discussion of the most promising stabilization methods for soil reinforcement and the outlook for the future. 相似文献
5.
6.
Toshio Nishi Hideyuki Nukaga So Fujinami Ken Nakajima 《高分子科学》2007,(1):35-41
Atomic force microscopy (AFM) has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young's modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young's modulus distribution image together with reconstructed real topographic image. Then we were able to recognize three regions; rubber matrix, carbon black (or bound rubber) and intermediate regions. Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space. 相似文献
7.
《Composite Interfaces》2013,20(7-9):581-604
To tailor the interaction across composite interfaces especially for the development of green composites, i.e. composites made completely from renewable materials, information about the fibre surfaces is required. We review the current state of the art of methods to determine the surface tension of natural fibres and discuss the advantages and disadvantages of techniques used. Although numerous techniques have been employed to characterise surface tension of natural fibres, it seems that commonly used wetting techniques are very much more affected by the non-ideal character of natural fibres. Inverse Gas Chromatography (IGC) is a much better suited technique to determine the surface energetic properties of natural fibres than wetting techniques. The surface tension of natural reinforcements, determined using IGC, was reported for nanosized bacterial cellulose as well as bamboo, cornhusk, flax, hemp and sisal, covering a wide range of cellulose content. The effect of methods to separate/extract fibres from the plants as well as of a few surface modification procedures on the fibre surface properties is also reviewed. The dispersive part of the natural fibre surface tension γ d S varies from 32 to 61 mJ/m2. The fibre surface tension increases with increasing cellulose content of natural fibres. We also found that a higher basicity (Donor Number, K B to Acceptor Number, K Aratio) was observed for fibres containing more cellulose. This may be reflective of higher crystalline cellulose content in the surfaces of the fibres, as only the ether linkage of the cellulose is labile for hydrogen bonding. 相似文献
8.
研究了通过烯丙基环状氨基甲酸酯的脱环羧化得到2-取代-△^3-哌啶和吡咯烷的机理, 并讨论了应用这一反应于新疆党参碱的全合成。 相似文献
9.
10.