Effects of Modification on Structure and Properties of Ramie Fiber/Polypropylene Composites

2010 ◽  
Vol 146-147 ◽  
pp. 441-444
Author(s):  
Wen Lei ◽  
Xiao Ming Jin

Ramie fiber and polypropylene were used as raw materials,ramie fiber/polypropylene composites were prepared by compression molding process,the effects of treating the ramie fiber with silane coupling agent and compatibilizing the composite with maleic anhydride gafted polypropylene(MAPP) on the structure, melting and mechanical properties of the composites were studied,the effects of immersion time in water on the mechanical properties of the composites were also investigated.The results show that,both the modification with coupling agent and by means of compatibilizing agent can strengthen the interfacial bonding between the fiber and matrix in the composite,and also improve its thermal stability.All the modified composites have greater strengths and moduli than the unmodified ones when immersed in water for any periods,especially the impact strength of the MAPP compatibilized composite not only increases with immersion time in water dramatically,but also is improved from that of the unmodified one by 104.84%,239.40%,294.48% and 320.01% respectively when immersed in water for 0,7,14 and 21d.

2008 ◽  
Vol 41-42 ◽  
pp. 313-316 ◽  
Author(s):  
Li Ping He ◽  
Yong Tian ◽  
Lu Lin Wang

Natural fiber reinforced polypropylene composites (NF/PP) have attracted a lot of attention because of their light weight, good mechanical properties, recyclable and environmental friendly features. This work has successfully fabricated ramie fiber reinforced polypropylene composites (RF/PP) with a hybrid method of melt-blending and injection molding. Different RF/PP eco-materials have been fabricated by varying the fiber length, fiber content and way of fiber pre-treatment. This paper studied the mechanical properties of the fabricated RF/PP composites in depth by investigating the mechanical behaviors of RF/PP and microstructures of the ruptured surfaces. The results show that the increases of fiber length and fiber content can improve the tensile strength, flexural strength and compression strength apparently, but result in negative influences on the impact strength and elongation behaviors of RF/PP composites. The optimal addition amount of ramie fiber is around 20 wt%. The pre-treatment of ramie fiber in 10%~15% NaOH is good to the mechanical properties of RF/PP. The fiber length can be varied in the range of 3-8 mm. It is expected that the fabricated RF/PP composites can be applied to automobile industry as environmental friendly eco-materials.


2010 ◽  
Vol 150-151 ◽  
pp. 406-409
Author(s):  
Wen Lei ◽  
Xiao Yan Ding ◽  
Chi Xu

Polypropylene and wood flour were used as raw materials,maleic anhydride grafted polypropylene(MAPP) as compatibilizing agent, wood-plastic composite(WPC) was prepared by compression molding process. The effects of the content of MAPP on the mechanical and thermal properties of WPC were investigated. The results show that, with the increase of the content of MAPP, both the tensile and flexural strengths of WPC will increase, and the impact strength of WPC increases first, then decreases, and the impact strength reaches the maximum of 1.18kJ/m2 when the content of MAPP is 4%,which is 76.7% increased from that of the composite without MAPP. Each composite has an obvious heat-absorption peak when melted during 140-170 and the melting enthalpy of WPC increases with the content of MAPP, the melting procedures of all the composites are quite similar with one another. Application of MAPP can improve the thermal stability of WPC


2015 ◽  
Vol 1767 ◽  
pp. 139-143
Author(s):  
Ramón Sánchez ◽  
Jacobo Aguilar ◽  
Silvia Y. Martínez ◽  
Reyes J. Sanjuan ◽  
Gerardo A. Mejía ◽  
...  

ABSTRACTDynamic mechanical properties of polypropylene (PP) and grafted polypropylene (PP-g-MA) composites reinforced with acetylated wheat straw fibers (WSF) is reported in this work. The materials were prepared with different fiber particle sizes (40, 80 and 140 U.S. mesh) and at different fiber contents (5, 10 and 15 wt.%). The PP and PP-g-MA composites, where anhydride maleic (MA) was used as coupling agent, were obtained using a twin-screw extruder; whereas an injection-molding machine molded the composite pellets into testing specimens. To observe the morphology of the composites, micrographs were taken with an optical microscope. The Dynamic mechanical properties were analyzed using a torsional rheometer. The morphological analysis showed a high porous structure somehow similar to foamed materials. The storage modulus (G′) increased by increasing the fiber content, and decreased with fiber particle sizes for the PP composites. Meanwhile, the use of the coupling agent additive promoted a modulus increase due to higher fiber-polymer interaction, from better adhesion and chemical bonds formation between the fibers-coupling agent-PP.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1643 ◽  
Author(s):  
Nabilah Afiqah Mohd Radzuan ◽  
Dulina Tholibon ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Che Hassan Che Haron

Automotive parts, including dashboards and trunk covers, are now fabricated through a compression-molding process in order to produce lightweight products and optimize fuel consumption. However, their mechanical strength is not compromised to avoid safety issues. Therefore, this study investigates kenaf-fiber-reinforced polypropylene composites using a simple combing approach to unidirectionally align kenaf fibers at 0°. The kenaf composite was found to withstand a maximal temperature of 120 °C. The tensile and flexural strengths of the aligned kenaf composites (50 and 90 MPa, respectively) were three times higher than those of the commercialized Product T (between 39 and 30.5 MPa, respectively) at a temperature range of 90 to 120 °C. These findings clearly showed that the mechanical properties of aligned kenaf fibers fabricated through the combing technique were able to withstand high operating temperatures (120 °C), and could be used as an alternative to other commercial natural-fiber products.


Author(s):  
Jamileh Shojaeiarani ◽  
Dilpreet Bajwa

Biopolymers are emerging materials with numerous capabilities of minimizing the environmental hazards caused by synthetic materials. The competitive mechanical properties of bio-based poly(lactic acid) (PLA) reinforced with cellulose nanocrystals (CNCs) have attracted a huge interest in improving the mechanical properties of the corresponding nanocomposites. To obtain optimal properties of PLA-CNC nanocomposites, the compatibility between PLA and CNCs needs to be improved through uniform dispersion of CNCs into PLA. The application of chemical surface functionalization technique is an essential step to improve the interaction between hydrophobic PLA and hydrophilic CNCs. In this study, a combination of a time-efficient esterification technique and masterbatch approach was used to improve the CNCs dispersibility in PLA. Nanocomposites reinforced by 1, 3, and 5 wt% functionalized CNCs were prepared using twin screw extrusion followed by injection molding process. The mechanical and dynamic mechanical properties of pure PLA and nanocomposites were studied through tensile, impact and dynamic mechanical analysis. The impact fractured surfaces were characterized using scanning electron microscopy. The mechanical test results exhibited that tensile strength and modulus of elasticity of nanocomposites improved by 70% and 11% upon addition of functionalized CNCs into pure PLA. The elongation at break and impact strength of nanocomposites exhibited 43% and 35% increase as compared to pure PLA. The rough and irregular fracture surface in nanocomposites confirmed the higher ductility in PLA nanocomposites as compared to pure PLA. The incorporation of functionalized CNCs into PLA resulted in an increase in storage modulus and a decrease in tan δ intensity which was more profound in nanocomposites reinforced with 3 wt% functionalized CNCs.


2012 ◽  
Vol 200 ◽  
pp. 321-324 ◽  
Author(s):  
Zhao Xia Wang ◽  
De Gao ◽  
Wen Cai Xu

Mechanical properties of the calcium-plastic composite have a great influence on the containers. The main factors affecting the mechanical properties are the process and material formulations. This paper mainly describes its impact of the addition of coupling agent. Under the usage of analysis of variance on single factor experiment, the mechanical properties of the calcium carbonate-plastic composite with three different coupling agents (silane, titanate and aluminate) were studied in the same test conditions. The results show that: The type and quantity of the coupling agent effect a lot on the mechanical properties of the composite. The silane coupling agent is the most suitable for calcium carbonate-plastic composite packaging materials, and the compatibility of calcium carbonate and polyethylene can be improved. When the silane coupling agent was at a 2.25 wt. % concentration, the tensile and flexural strength were improved obviously, especially the tensile strength increased by 23.24%, but the impact strength improved slightly.


2008 ◽  
Vol 144 ◽  
pp. 267-272
Author(s):  
Alexander S. Chaus

In order to exhibit good all-round performance the impact toughness enhancement of cast high-speed steels (HSS) is obligatorily needed. In general, different methods are used commercially to achieve cast structure refinement and, as a consequence, their properties are improved. Introduction into the melt of inoculants particles or surface-active additions is among most beneficial. However, the effect of modifying additions in cast HSS has been studied insufficiently. For this reason the theoretical evaluation and experimental confirmation of the modifying and refining effects of 23 chemical elements in HSS have been carried out. The relationships between the structural parameters and mechanical properties in the M2 and T30 HSS have been established.


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