Maleated Coupling Agents Research Articles

Effect of coupling agents on properties of vegetable fiber polymeric composites: review

Using natural fibers in composites presents a wide range of applications, from furniture to airplanes. In polymeric composite, the use of fiber is to boost strength and stiffness. However, this material presents low mechanical properties compared to virgin polymers due to hydrophilic nature of the fiber and hydrophobic nature of the polymer. It can result in weak bonding matrix/fiber which may cause incompatibility problem in bonding fibers with most of the polymer matrices. To achieve compatibility between surfaces there is a need to modify them, and one alternative is using coupling agents. Maleated coupling agents stand out as option, but their source is petroleum-derived polyolefin. Researchers have been seeking for more environmentally friendly alternatives to replace these materials. Therefore, this work aims to bring a comprehensive review of the mechanical behavior of maleated and ecological coupling agents. Based on the literature, resistance, flexural, and tensile strength were properties discussed.

Recycled Multi-Material Packaging Reinforced with Flax Fibres: Thermal and Mechanical Behaviour.

In this work, the use of a recycled mix stemming from the treatment of multilayer aseptic packaging used in the food and beverage industry is proposed as the matrix for short fibre composites reinforced with flax fibres, to generate value-added materials in contrast to the more common end-of-life scenario including energy recovery. This is expected to be a preferred choice in the waste hierarchy at the European level. A commercially available material (EcoAllene) obtained from multilayer packaging recycling was compounded with short flax fibres up to 30 wt.% by twin screw extrusion, with a view to enhancing its poor mechanical profile and broadening its applications. Composites were in depth analyzed by thermogravimetric analysis and differential scanning calorimetry, which highlighted the complex nature of this recycled product, a limited nucleation ability of flax fibres and a lower thermal stability due to the premature degradation of natural hemicellulose and cellulose, though featuring in any case onset degradation temperatures higher than 300 °C. Composites’ mechanical properties were assessed in tension, bending and impact conditions, with remarkable improvements over the neat matrix in terms of stiffness and strength. In particular, at 30 wt.% fibre content and with 5 wt.% of maleated coupling agent, an increase in tensile and flexural strength values by 92% and 138% was achieved, respectively, without compromising the impact strength. The effectiveness of flax fibres confirmed by dynamo-mechanical analysis is beneficial to the exploitation of these composites in automotive interiors and outdoor decking applications.

Chemical, Thermal and Mechanical Characterization of Licorice Root, Willow, Holm Oak, and Palm Leaf Waste Incorporated into Maleated Polypropylene (MAPP).

The effect of four lignocellulosic waste fillers on the thermal and mechanical properties of biocomposites was investigated. Powdered licorice root, palm leaf, holm oak and willow fillers were melt compounded with polypropylene at two different weight contents, i.e., 10 and 30, and then injection molded. A commercially available maleated coupling agent was used to improve the filler/matrix interfacial adhesion at 5 wt.%. Composites were subjected to chemical (FTIR-ATR), thermal (TGA, DSC, DMA) and mechanical (tensile, bending and Charpy impact) analyses coupled with a morphological investigation by scanning electron microscopy. Although similarities among the different formulations were noted, holm oak fillers provided the best combination of thermal and mechanical performance. In particular, at 30 wt.% content with coupling agent, this composite formulation displayed remarkable increases in tensile strength and modulus, flexural strength and modulus, of 28% and 110%, 58% and 111%, compared to neat PP, respectively. The results imply that all these lignocellulosic waste fillers can be used successfully as raw materials for biocomposites, with properties comparable to those featured by other natural fillers.

Investigations on chemical behaviours on mechanical properties of natural fiber Composites: An evaluation

Natural fibers are the replacement for the readymade fiber to fiber–strengthened mixtures have improved and unlocked extra business opportunities and potentials. Conventional fiber offers both savings in the cost and decrease in compactness when likened to the cut-glass fibers. This review article highlights some of the important breakthroughs associated with the different chemical treatments of natural fiber composites. To increase the surface properties and to avoid the drawbacks of natural fibers chemical treatments such as alkali, silane, acetylation, benzoylation, acrylation, maleated coupling agents, isocyanates, permanganate are proposed. The application of chemical conduct improves the bond among the fibers and also increases the fiber strength and because of this aquatic captivation of mixtures is abridged and their powered possessions are better. Also it covers some emerging applications, Industrial applications and automotive applications related to natural fiber composites.

Environmental impact and effect of chemical treatment on bio fiber based polymer composites

In recent years, bio fibers (such as jute, hemp, flax, nettle, etc) are gaining more attention due their light weight, high specific strength, biodegradability, etc in various applications. Along with this, environmental issue is also an important aspect for maintaining sustainability of the bio fiber based composites. Failure occurs in bio fiber based polymer composites when they are applied to severe loading conditions and the material start degrading. To sustain the lifetime of the bio fiber composites, chemical treatment of the bio fiber is done to enhance the mechanical strength between the bonds so that the amount of stress transferability in the composites is equalized. The most important chemicals sources for the treatments are alkaline, silane, acetylation, benzoylation, acrylation, maleated coupling agents, permanganate, peroxide, isocyanate, stearic acid, sodium chlorite, triazine, derivatives of fatty acids (oleoyl chloride). The present study summarises the studies carried out on the environmental impact and various chemical treatments that were applied to bio fibers for enhancing their properties.

Chemical, biological, and nanoclay treatments for natural plant fiber-reinforced polymer composites: A review

Natural plant fiber-reinforced polymer composites have been in the limelight in the field of materials science for their mechanical properties, economy, and eco-friendliness. Properties of such novel composites depend on the adhesion and interaction between the fibers and the polymer matrix. Consequently, poor interaction can lead to declined mechanical properties, particularly strength. Surface modifications of fibers are carried out to enhance the bonding with the matrix by certain chemical treatments that remove hydroxyl groups in the amorphous cellulose region, making them hydrophobic and hence compatible with the matrix. Doing so also strengthens the composites, widening their scope of application. This review article provides comprehensive information about various surface modification techniques that include alkali, silane, acetylation, permanganate, peroxide, benzoylation, acrylation, acrylonitrile grafting, isocyanate, addition of maleated coupling agents, and fungal treatments. The working mechanisms and the effects of such treatments on mechanical strength are also elucidated. Furthermore, this review provides an overview of nanoclay inclusion in polymers, their addition techniques, and the augmentation of the mechanical properties of polymer matrix composites. The article concludes along with the field of applications, summary of pertinent challenges, and directions for future work.

Quasi-Static and Low-Velocity Impact Behavior of Intraply Hybrid Flax/Basalt Composites

In an attempt to increase the low-velocity impact response of natural fiber composites, a new hybrid intraply woven fabric based on flax and basalt fibers has been used to manufacture laminates with both thermoplastic and thermoset matrices. The matrix type (epoxy or polypropylene (PP) with or without a maleated coupling agent) significantly affected the absorbed energy and the damage mechanisms. The absorbed energy at perforation for PP-based composites was 90% and 50% higher than that of epoxy and compatibilized PP composites, respectively. The hybrid fiber architecture counteracted the influence of low transverse strength of flax fibers on impact response, irrespective of the matrix type. In thermoplastic laminates, the matrix plasticization delayed the onset of major damage during impact and allowed a better balance of quasi-static properties, energy absorption, peak force, and perforation energy compared to epoxy-based composites.

Effect of basalt fibre hybridisation and sizing removal on mechanical and thermal properties of hemp fibre reinforced HDPE composites

Despite the advantages offered by natural fibre-based thermoplastic composites in terms of environmental impact and cost, their mechanical performance is generally lower than that of synthetic counterparts. Hybridisation with mineral fibres (basalt) can broaden the industrial applications of natural fibre reinforced composites. The present study focused on the performance of injection-moulded short basalt fibre, hemp fibre and hemp/basalt fibre hybrid high density polyethylene (HDPE) composites. Effects of a maleated coupling agent on the thermal and mechanical properties of the resulting composites were evaluated as a function of the fibre mass fraction. Hybridisation of hemp fibres with basalt fibres was found to significantly increase the mechanical properties and the crystallinity of hemp-fibre reinforced composites thus suggesting that short hemp/basalt fibre hybrid HDPE composites are promising candidates for semi-structural applications. Additionally, a sizing removal procedure mimicking the conditions experienced in an end-of-life composite thermal recycling process was defined and discussed in terms of residual mechanical properties of basalt/HDPE composites.

Recent development and future trends in coir fiber‐reinforced green polymer composites: Review and evaluation

Development of natural fiber composites with thermoplastics and thermosets finds applications in various fields, from agriculture to automotive. It can reduce the dependency on petroleum resources which causes several environmental problems. Natural fibers are renewable and biodegradable that reduces carbon footprint to the environment. Coir fibers are natural fibers used in the development of composites offers comparable properties with other mineral fillers. This article reviews different methods of coir fiber modification include alkali treatment, silane treatment, hydrogen peroxide treatment, sodium hypochlorite treatment, sodium periodate treatment coupled with p‐aminophenol and urea, treatment with benzene diazonium salt and maleated coupling agent. It also reviews composites of coir fiber with thermoplastic, rubber and thermoset plastics. Hybrid composites based on coir fiber are also being discussed. Thermoplastic composites such as biodegradable (PLA, PBS) and petroleum‐based polymers (PE, PP) and thermoset polymers include polyurethane, epoxy and polyester based composites also reviewed. Degradation and biodegradation studies were reviewed in the case of biodegradable polymers. Hybrid fibers of coir with other natural and mineral fibers have recently been used in composite industry has also been reviewed. All these composites show better properties. It can be used in different applications in the field of automobile, building and construction, consumer products and furniture. POLYM. COMPOS., 37:3296–3309, 2016. © 2015 Society of Plastics Engineers

The effect of pre-impregnation with maleated coupling agents on mechanical and water absorption properties of jute fabric reinforced polypropylene and polyethylene biocomposites

Maleic anhydride functionalized polymers were used as compatibilizer in jute fabric reinforced polypropylene- and polyethylene-based composites. Composites were produced from pristine jute fabric, alkaline-treated jute fabric and compatibilizer solutions pre- impregnated jute fabrics. Polypropylene-grafted maleic anhydride and a random terpolymer of ethylene, acrylic ester and maleic anhydride were used as compatibilizer for polypropylene and polyethylene, respectively. The effect of alkaline treatment and pre-impregnation on mechanical, water absorption and morphological properties of composites were investigated. Both alkaline treatment and pre-impregnation increased the mechanical properties and reduced the water uptake of composites. The highest improvement in mechanical properties and the highest reduction in water uptake values were achieved when alkaline treatment and pre-impregnation were used together for both matrix types. Tensile strength of pristine jute fabric reinforced polypropylene- and polyethylene-based composites increased at about 90% and 40% when alkaline treatment and pre-impregnation were used together, respectively.

Chemical treatments on plant-based natural fibre reinforced polymer composites: An overview

This paper provides a comprehensive overview on different surface treatments applied to natural fibres for advanced composites applications. In practice, the major drawbacks of using natural fibres are their high degree of moisture absorption and poor dimensional stability. The primary objective of surface treatments on natural fibres is to maximize the bonding strength so as the stress transferability in the composites. The overall mechanical properties of natural fibre reinforced polymer composites are highly dependent on the morphology, aspect ratio, hydrophilic tendency and dimensional stability of the fibres used. The effects of different chemical treatments on cellulosic fibres that are used as reinforcements for thermoset and thermoplastics are studied. The chemical sources for the treatments include alkali, silane, acetylation, benzoylation, acrylation and acrylonitrile grafting, maleated coupling agents, permanganate, peroxide, isocyanate, stearic acid, sodium chlorite, triazine, fatty acid derivate (oleoyl chloride) and fungal. The significance of chemically-treated natural fibres is seen through the improvement of mechanical strength and dimensional stability of resultant composites as compared with a pristine sample.

Role of Maleated Coupling Agents on the Interface Adhesion of Polypropylene—Wood Composites

The main accomplishment of compounding wood-flour with thermoplastics is an increase in rigidity and specific strength. Filler—matrix interactions play a key role in the composite performance and the strength of the interface is determined by the nature of the coupling agents employed. The coupling efficiency of maleated polypropylene (PP-MAH) with varying MAH content and melt flow index in polypropylene—wood composites has been investigated. A method based on a simplified single rule of mixtures aiming to compare differences in interface adhesion in the presence of PP-MAH is proposed in terms of relaxation spectra of polypropylene—wood composites obtained by dynamic-mechanical thermal analysis (DMTA). The criterion is an attempt to determine an adhesion factor as derived from the relative mechanical damping (tan δ) of the composite as a function of the filler content and temperature. Experimental results deviate from model predictions possibly owing to assumptions of wood-flour as a rigid filler as well as neglect of an interphase volume fraction and its damping characteristics. However, good correlations of coupling efficiency and yield properties have been found for wood composites with homopolymer and copolymer matrices within a range of varying wood-flour content and type of coupling agent. Further evidences of improved matrix—filler interactions, wettability, and filler dispersion in the presence of the PP-MAH are observed by scanning electron microscopy.

Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites: A Review

Studies on the use of natural fibers as replacement to man-made fiber in fiber-reinforced composites have increased and opened up further industrial possibilities. Natural fibers have the advantages of low density, low cost, and biodegradability. However, the main disadvantages of natural fibers in composites are the poor compatibility between fiber and matrix and the relative high moisture sorption. Therefore, chemical treatments are considered in modifying the fiber surface properties. In this paper, the different chemical modifications on natural fibers for use in natural fiber-reinforced composites are reviewed. Chemical treatments including alkali, silane, acetylation, benzoylation, acrylation, maleated coupling agents, isocyanates, permanganate and others are discussed. The chemical treatment of fiber aimed at improving the adhesion between the fiber surface and the polymer matrix may not only modify the fiber surface but also increase fiber strength. Water absorption of composites is reduced and their mechanical properties are improved.

Maleated coupling agents for natural fibre composites

Abstract Maleated coupling agents are widely used to strengthen composites containing fillers and fibre reinforcements. The established role of MaPOs results from two main factors, economical manufacturing and the efficient interaction of maleic anhydride with the functional surface of fibre reinforcements. Peak performance was demonstrated in agrofibre polypropylene composites by selecting a maleated coupler that has the appropriate balance of molecular weight and maleic anhydride content. The flexural and tensile strengths of the 30% agrofibre composites increased by more than 60% with Epolene™ G-3015. Newly developed MaPE couplers for the wood-polyethylene market demonstrate superior performance compared against other potential polyolefin coupling agents. Results indicate that the new polyethylene couplers at 3% loading can double the tensile strength and triple the impact properties compared to non-coupled blend of wood and polyethylene.

Effectiveness of Maleated and Acrylic Acid-Functionalized Polyolefin Coupling Agents for HDPE-Wood-Flour Composites

The performance of fiber reinforced thermoplastic composites strongly depends on solid fiber-matrix adhesion to allow stress transfer between the phases. Fiber surface modification with coupling agents is generally needed to induce bond formation between the fiber and the polymer. This study investigated the effects of coupling agent's functional monomer (acrylic acid vs. maleic anhydride) and base resin (polyethylene (PE) vs. polypropylene (PP)) types on the tensile and flexural properties of high-density polyethylene (HDPE)-wood-flour composites. The interfacial adhesion between wood flour and HDPE matrix was examined using environmental scanning electron microscope. The experimental results indicate that the types of functional monomer and base resin are important factors determining the effectiveness of functionalized coupling agents for HDPE-wood-flour composites. Maleic anhydride-functionalized polyolefins perform better than acrylic acid counterparts whereas PE-based maleated coupling agents are more effective than PP-based counterparts in improving the strength properties of HDPE-wood-flour composites.