A growing concern of climate change and waste pollution is causing a shift in products towards green materials. The automotive industry is exploring environmentally friendly alternatives to glass fibers (GF). This research focuses on understanding interactions between constituents of biocomposites made up of basalt fiber (BF) and hemp hurd particle fiber (HF) reinforced polypropylene (PP), and statistically comparing the mechanical properties. The addition of a coupling agent has significantly improved the performance and fiber-matrix interactions in the biocomposite blends. The elastic modulus of some BF/HF/PP mixtures were comparable to the GF/PP composite; however, the GF still outperformed in strength. Rotational and capillary rheometer analysis determined the viscosities of all formulations displaying that basalt composites were consistently lower in viscosity than the glass fiber composite, indicating easier processing conditions.
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Evaluation of the Rheological and Mechanical Properties of Mixed Plastic Waste-Based Composites
This study evaluated the mechanical, thermal, water soak, and rheological properties of mixed plastic waste (MPW) in combination with fibers derived from residual hops bines and coupling agents or dicumyl peroxide (DCP) to form composite materials. Hop bines were pulped to afford individual hop fibers (HF) in 45% yield with 78% carbohydrate content. The MPW comprised mainly of PET, paper, PE and PEVA. Tensile moduli and strength of the formulations ranged between 1.1 and 2.0 GPa and 11 and 14 MPa, respectively. The addition of hops fiber (HF) improved the tensile modulus of the formulations by 40%. Tensile strength was improved by the addition of coupling agents by 11% and this was supported by determining the adhesion factor by dynamic mechanical analysis. However, the addition of DCP resulted in a reduction of tensile properties. The melt properties of the formulations showed shear thinning behavior and followed the power-law model. The water absorption tests for most of the MPW formulations gave an 11% weight gain over 83 d except for the DCP treated composites (14–16%). The fabricated composites can be used in non-structural applications such as (garden trim, siding, pavers, etc.).
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- Award ID(s):
- 1827364
- NSF-PAR ID:
- 10359076
- Date Published:
- Journal Name:
- Waste and Biomass Valorization
- ISSN:
- 1877-2641
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Thermoplastic polyamide 6 composites reinforced with flax fiber fabric and kraft pulp cellulose mat were prepared by anionic
in situ ring‐opening polymerization (ROP) using a special vacuum‐assisted resin infusion process. The effects of the polymerization initiator, fiber alkali pre‐treatment, fiber type, polymerization temperature, and surface modification of fibers with organosilane coupling agents on the ROP reaction, polymer conversion and the physical and mechanical properties of the composites were investigated. The results showed that a combination of alkali pre‐treatment and the use of relatively less reactive magnesium bromide based anionic initiator gave a successful ROP reaction and high polymer conversion. Analysis of the physical and mechanical properties of the composite panels showed that optimal mechanical properties could be achieved by using a polymerization temperature of 150°C while polymerization at higher temperatures lowered both the flexural and tensile properties due to generation of more internal microvoids, as well as, decreased crystallinity of the matrix. In addition, it was found that optimal mechanical properties of the composites could be obtained using 2 wt% aminopropyltriethoxysilane (APS) coupling agent while higher APS concentrations negatively impacted the interfacial adhesion, resulting in lower mechanical properties. POLYM. COMPOS., 40:1104–1116, 2019. © 2018 Society of Plastics Engineers -
Natural fiber-reinforced polymers are currently used in a variety of low- to high-performance applications in the automotive, packaging, and construction industries. Previous studies have demonstrated that natural fibers (e.g., flax, hemp) exhibit good tensile mechanical properties and have positive environmental and economic attributes such as low cost, rapid renewability, and worldwide availability. However, natural fibers are inherently susceptible moisture-induced changes in physical and mechanical properties, which can be unfavorable for in-service use. This study illustrates how a micromechanics-based modelling approach can be used to help facilitate durability design and mitigate the deleterious effects of freeze-thaw deterioration in wood-plastic composites (WPCs). The model described in this study predicts the critical fiber volume fraction (V_fcrit) at which damage to the composite will occur under certain environmental conditions for different WPC formulations of hardwood and softwood fiber reinforcement and polymer matrix types. As expected, the results show that V_fcrit increases (a positive result) as anticipated in situ moisture content decreases. In addition, results suggest that fiber packing distribution directly influences V_fcrit and that V_fcrit increases as the mechanical properties of the polymer matrix increase. In sum, the study demonstrates how predictive modeling can be applied during the design phase to ensure the durability of WPCs.more » « less
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null (Ed.)Fully biodegradable unidirectional green composites with excellent tensile properties were fabricated by combining one of the highest specific strength liquid crystalline cellulose (LCC) fibers as the reinforcement and microfibrillated cellulose (MFC) strengthened nonedible avocado seed starch (AVS)-based resin. MFC/AVS resin was crosslinked using 1,2,3,4-butane tetracarboxylic acid as well as plasticized using sorbitol or glycerol. Combination of alkali, mechanical and thermal treatments improved LCC fiber fracture stress from 1.5 GPa to over 1.9 GPa and Young’s modulus from 49 to 64 GPa. While the type and amount of plasticizer used changed the fracture strain of MFC/AVS resin, they also showed significant influence on the mechanical properties of the unidirectional composites. These composites prepared by hand lay-up, based on modified LCC fibers resulted in fracture stress of over 380 MPa and Young’s modulus of 19.5 GPa with less than 40% fiber content. Results suggest that there is scope to improve the properties further by using higher fiber content and automated manufacturing. These ‘green’ composites with excellent strength and stiffness may be used in many applications such as construction, automobile and others.more » « less
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Herein, the enhancement of the mechanical properties of microwave absorption composites, multiwalled carbon nanotubes (MWCNTs)–epoxy with various MWCNT loadings, using glass fiber (GF) reinforcement is focused upon. The tensile strength, morphologies, dielectric permittivity, and electromagnetic (EM) wave absorption properties (in a frequency range from 1 to 26 GHz) of the composites are investigated. The tensile strength of the composites is enhanced to about 400 MPa, which is comparable with that of commercial aluminum alloy 6061 (about 300 MPa), whereas the tensile strength of the pristine MWCNT–epoxy composite is around 15 MPa. The mass density of the MWCNT–epoxy–GF composites herein is found to be around 1.6 g cm−3, whereas aluminum alloy 6061 has a mass density of ≈2.7 g cm−3. In addition, the MWCNT (9 wt%)–epoxy–GF composite presents a strong EM wave absorption in a wide frequency band from 14 to 26 GHz, whereas aluminum alloys do not have much EM wave absorption. The high microwave absorption together with the enhanced mechanical strength of the composites provides a multifunctional potential for some applications.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s12649-022-01794-x
