scholarly journals Effects of rice husk fibers on the properties of mixed-particle-size fiber-reinforced polyvinyl chloride composites under soil accelerated aging conditions

2019 ◽  
Vol 14 ◽  
pp. 155892501987928
Author(s):  
Lei Wang ◽  
Chunxia He

In this article, rice husk fiber/polyvinyl chloride composites were prepared and analyzed. The optimal composition of mixed-particle-size fiber-reinforced composites was determined through orthogonal experimentation. The physical, mechanical, and thermal properties of the mixed-particle-size fiber-reinforced composites were compared to unprocessed (100 mesh) rice husk fiber/polyvinyl chloride composites. The surface microscopic appearances of the unprocessed and final composites were observed via laser microscope. Long-term accelerated soil aging caused micro-cracks to appear on the surfaces of the composites. Interfacial adhesion was observed via scanning electron microscopy. The results indicated that mixed-particle-size fibers can better fill interfacial gaps, leading to strong interfacial adhesion. Furthermore, the addition of mixed-particle-size fibers improves the soil aging resistance of composites. The hardness, flexural strength, impact strength, and first onset pyrolysis temperature (after 0 days) increase from 50 HRR, 35.2 MPa, 3.19 KJ/m2, and 258.5°C to 55 HRR, 39.4 MPa, 3.86 KJ/m2, and 261.2°C, respectively. However, the mass loss rate and thickness expansion rate (after 21 days) decrease from 2.9% and 0.79% to 2.21% and 0.74%, respectively. In general, the addition of mixed-particle-size fibers improves the ultimate properties of composites under soil aging conditions.

2021 ◽  
pp. 095400832110089
Author(s):  
Ting Li ◽  
Zengxiao Wang ◽  
Hao Zhang ◽  
Yutong Cao ◽  
Zuming Hu ◽  
...  

The poor interfacial adhesion of aramid fiber and matrix limits the application of the final composites. In this study, a series of the sulfone-functionalized poly( p-phenylene terephthalamide) (SPPTA) copolymers were satisfactorily synthesized and the effects of polymerization conditions (contents of the additional monomer and the cosolvent LiCl, molar concentration and ratio of the monomer, reaction temperature and time) on the molecular weight of the copolymer were discussed. The introduction of the sulfone group in aromatic polyamides not only increased the polarity of poly( p-phenylene terephthalamide) (PPTA) but destroyed the regular arrangement of the molecular chains, which greatly improved the surface free energy and the solubility of the polymers in organic solvents. The polymer maintained excellent thermal and interfacial properties. Compared with the PPTA fiber/epoxy composites, the interfacial shear strength (IFSS) of SPPTA fiber-reinforced epoxy composites reached 43.5 MPa, with a significantly enhancement of 20.8%, implying that the study provided an effective method to achieve highly interfacial adhesion of aramid fiber-reinforced composites.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 654 ◽  
Author(s):  
Tufail Hassan ◽  
Hafsa Jamshaid ◽  
Rajesh Mishra ◽  
Muhammad Qamar Khan ◽  
Michal Petru ◽  
...  

The use of acoustic panels is one of the most important methods for sound insulation in buildings. Moreover, it has become increasingly important to use green/natural origin materials in this area to reduce environmental impact. This study focuses on the investigation of acoustic, mechanical and thermal properties of natural fiber waste reinforced green epoxy composites. Three different types of fiber wastes were used, e.g., cotton, coconut and sugarcane with epoxy as the resin. Different fiber volume fractions, i.e., 10%, 15% and 20% for each fiber were used with a composite thickness of 3 mm. The sound absorption coefficient, impact strength, flexural strength, thermal conductivity, diffusivity, coefficient of thermal expansion and thermogravimetric properties of all samples were investigated. It has been found that by increasing the fiber content, the sound absorption coefficient also increases. The coconut fiber-based composites show a higher sound absorption coefficient than in the other fiber-reinforced composites. The impact and flexural strength of the cotton fiber-reinforced composite samples are higher than in other samples. The coefficient of thermal expansion of the cotton fiber-based composite is also higher than the other composites. Thermogravimetric analysis revealed that all the natural fiber-reinforced composites can sustain till 300 °C with a minor weight loss. The natural fiber-based composites can be used in building interiors, automotive body parts and household furniture. Such composite development is an ecofriendly approach to the acoustic world.


Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1128 ◽  
Author(s):  
Dengxun Ren ◽  
Lin Chen ◽  
Yue Yuan ◽  
Kui Li ◽  
Mingzhen Xu ◽  
...  

The interfacial properties between fibers and resin matrices show great influence on the properties of fiber-reinforced composites. In this work, phthalonitrile containing benzoxazine (BA-ph) was chosen as the resin matrix, which combined with the glass fiber (GF) to prepare reinforced composite laminates at low temperature (200 °C). The poly(arylene ether nitrile) (PEN) was used to modify the GF and BA-ph matrix. Curing behaviors of the BA-ph/PEN were investigated with Differential scanning calorimetric (DSC) and Dynamic rheological analysis (DRA), and results indicated that the polymerization would be hindered by PEN due to the dilution effects. Moreover, the formation of triazine rings which assigning to the ring-forming polymerization of nitrile groups in BA-ph and PEN could improve the compatibility of BA-ph and PEN in the matrix. The SEM images of the fracture surface of the composites revealed that the brittleness of BA-ph matrix and interfacial adhesion between GFs and matrix was improved. The enhanced interfacial adhesion was detailedly discussed from the perspective of physical entanglement and the copolymerization between PEN chains on the surface of GFs and BA-ph/PEN matrix. The results of DMA also explained the toughness of BA-ph/PEN matrix, the semi-interpenetrating polymer networks and the interfacial adhesion. In sum, a feasible strategy that modifies the surface of GFs and the brittleness of the thermosetting matrix by high-performance thermoplastic polymers, which can be employed to prepare the composite laminates with improved properties.


2020 ◽  
pp. 002199832095318
Author(s):  
RMR Shagor ◽  
F Abedin ◽  
R Asmatulu

The use of nanofillers to enhance the properties of fiber reinforced composites is limited due to the adverse effect on mechanical properties caused by agglomeration of these nanofillers in the matrix materials. In this study, graphene nanoflakes were functionalized with silane moiety to improve its dispersion, stability and bond strengths in the polymer matrices of the carbon fiber reinforced composites. Wet layup process was applied to incorporate graphene nanocomposites into the dry carbon fibers to make composite panels following the curing cycle of the epoxy and hardener. The impacts of the functionalized graphene on the mechanical and thermal properties of carbon reinforced composite were investigated in detail by tensile test, differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy (SEM) analysis. It was observed that nanocomposites with 0.5 wt% silanized graphene exhibited maximum tensile strength and modulus of elasticity, indicating that 0.50 wt% silane functionalized graphene was the optimum nanofiller composition amongst the three different compositions investigated. The nanocomposites with 0.25 wt% and 0.50 wt% nanofillers showed improved ductility compared to the control sample. Based on the SEM studies on the crack zones, major morphological changes were observed after the salinization process. The interfacial interaction between epoxy and silane moiety of the graphene and reduction in the tendency to agglomerate could account for the improved properties of the nanocomposite observed here. Nanocomposites with silanized graphene showed overall higher glass transition temperature (Tg) and tensile strength than those with pristine graphene and control samples.


2011 ◽  
Vol 67 (3) ◽  
pp. 527-540 ◽  
Author(s):  
Xiaokang Zhang ◽  
Yaoxian Wang ◽  
Chong Lu ◽  
Shujun Cheng

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