Tailoring the Properties of Biocomposites by Silane Coupling Agents and Graphene Nanoplatelets

The increase in environmental awareness and stringent regulations from concerned governing bodies are the main driving forces for the growing interest in biomaterials. The development of environment-friendly bio-composites and their application in various industrial sectors has steadily increased during the last few decades. Wood-based, natural, and man-made fibres are used to manufacture bio-composites. The polymer matrix can be thermoset resins like epoxy (EP) or unsaturated polyester resin (UPR), or thermoplastic polymers like polypropylene (PP), polyethylene (PE) and polyvinyl chloride (PVC). The primary resource to produce regenerated cellulose fibre (RCF) or man-made cellulose fibres is wood. The regenerated cellulose fibres, which are commonly named viscose or rayon, possess high purity, uniformity and reproducibility of their properties. Compared to lignocellulosic fibres, the benefit of man-made cellulose is that it is available in continuous filaments. When it comes to the lignocellulosic fibre or regenerated cellulose fibre reinforced composites, the interface between fibre and matrix polymer plays a vital role. The hydrophilic wood-based fibres and hydrophobic thermoplastic polymer composites result in structurally weak composites due to the non-compatible interaction across the interface. Though the chemical modification techniques for wood fibre based composites are well-known, that of RCF-based composites requires more research. Few studies report the use of the chemical modification of viscose fabric to be used in composite production. The chemicals used in the modification step necessitate waste treatment, which involves extra energy consumption, time and money. Hence an environmentally friendly and sustainable approach to improve fibre-matrix adhesion is necessary. In the Nordic countries with abundant raw material sources, the forest industry explores new applications for the produced side-streams. The building and construction, automotive and household commodities are the primary markets for wood-plastic composites (WPCs). By exploring new markets for WPC's, the composite industry and the forest industry will gain larger markets and better commercial profits from wood and its by-products. One approach for finding a new market for WPC's is to develop extrinsically conductive composites containing conductive fillers. The research in functionalising the WPC is in the developing stage, and it requires profound research. This thesis aims to improve the interfacial adhesion in viscose fabric/thermoset resin-based composites by chemically modifying the viscose fabric. In another approach, the thermoset resin (epoxy resin) is modified with an appropriate silane coupling agent as an alternative to fibre surface modification, and its effect on various properties of composites is studied. Another objective of the study is to produce and characterise wood-plastic composites containing electrically and thermally conductive nanofillers. The effect of incorporating graphene nanoplatelets (GNP) on various properties of polypropylene-based WPC is studied. These types of composites can be a sustainable solution for the extrinsically conductive polymer market. The silane coupling agents such as 3-aminopropyltriethoxysilane (APTES), 3-methacryloxypropyltrimethoxysilane (MPS) and also acetylation treatment are adopted to modify the viscose fabrics. The unsaturated polyester-based composites prepared from viscose fabric modified by APTES in ethanol medium increased the flexural strength and notched Charpy impact strength by 18% and 115%, respectively. The water absorption studies revealed that the APTES modification significantly delayed and reduced the total absorbed water compared to all other composites. As an alternative to the fibre modification method, epoxy resin was modified by APTES to produce viscose fabric reinforced composites. The epoxide content determination and FTIR results from this study show that resin modification efficiency was better at 70oC compared to modification done at room temperature. The APTES was mixed directly into the epoxy resin, eliminating any process waste in the modification stage. The tensile strength and elongation at break of the composites prepared using APTES- modified epoxy resin increased by 14% and 41%, respectively. The Charpy impact strength of APTES-modified epoxy resin based viscose fabric composites increased by 115%. The effect of GNP on various properties of WPC was studied. The addition of graphene into PP-based WPC yielded an anti-static/dissipative WPC compound at a graphene loading of 15 wt%. The surface resistivity of PP/wood/graphene composite decreased by several orders of magnitude from 1014 Q/sq to 106 Q/sq. While achieving the desired electrical properties, the tensile strength of hybrid WPC decreased by 25%. The thermal conductivity of WPC containing 20 wt% wood filler and 15 wt% GNP increased by 130% compared to WPC comprising 20 wt% wood filler

SUSTAINABLE BOAT DESIGN GUIDE: Materials, Manufacturing, End-of-Life and Environmental impact

The fiber-reinforced plastic composite components consist of fiber reinforcements (glass, carbon, aromatic polyamide fibers) embedded in resin (epoxy, polyester, phenol-formaldehyde). While the resin gives the composite its shape, surface appearance, environmental tolerance, and overall durability, the fibrous reinforcement bears most of the structural loads, thus primarily providing macroscopic stiffness and Strength. Due to the chemical crosslinked structures, thermoset composites cannot be easily separated into their fiber and matrix components, which is the basis for the success of these versatile materials but also means they are inherently difficult to recycle. Additionally, the production of the fibers mentioned above is energy-intensive and consumes non-renewable resources. Therefore, adopting sustainable alternatives for synthetic fibers and resins in production is essential for the industry to move to a circular economy model from the current linear model

LIFE CYCLE ASSESSMENT OF STEERING CONSOLE USED IN BOAT

The Veneprint project’s primary goal is to create conditions for boat industry companies to transform from a linear economic model to a circular. This transformation is envisaged through the utilization of partially or entirely bio-based, as well as recyclable, materials and robotized 3D printing production technology. The project’s measures will reduce the carbon footprint of boat companies, improves working conditions for workers and therefore improves overall sustainability. The use of recyclable material with potential to reuse it strengthens companies’ competitiveness and provides cost-effective and environmentally friendly solutions to customers, while 3D printing technology enables better customization of the boat features. Furthermore, Veneprint project activities accelerate business development by promoting investments in new modern technologies and pave the way for new value chains, which can be exploited locally

Forestry wastes filled polymer composites for agricultural use

Two kinds of polymer composites were prepared using poly (vinyl alcohol) as binder and forestry or wood processing wastes as fillers. In one kind of the composites pine needle meal was used as filler while the other kind of the composites was filled with pine bark meal. Glycerol and oleic acid were used for the modification of mechanical, sorption properties and solubility of the composites. The films of the composites were fabricated and their mechanical, viscoelastic and antifungal properties as well as water absorption and solubility in water were studied. Mathematical experiment design was used to evaluate influence and importance of both glycerol and oleic acid content on of mechanical properties, solubility and water absorption of the composite films filled with pine bark meal. The second order polynomial models were developed in order to find out optimal content of both glycerol and oleic acid in compositions. Exploitation properties of the composite pots prepared from the composites were studied and vegetation tests were performed. It was shown that evaporation rate of water through the walls of the composite pots was by 45% lower and the temperature of substrate in the composite pots was by 3e4 C higher as compared with the corresponding characteristics of peat pots. Plants cultivated in the composite pots had better developed root system relative to those cultivated in peat potsGamtos tyrimų centrasKauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij

Modification of epoxy resin by silane-coupling agent to improve tensile properties of viscose fabric composites

The modification of epoxy resin by 3-aminopropyltriethoxysilane (APTES) to improve the tensile properties of warp knitted viscose fabric composites is reported in this study. The study evaluates the efficiency of modification methods adopted to modify the epoxy resin and the influence of the resin modification on various properties of the cured castings. The influence of matrix resin modification on the tensile properties of viscose fabric composite is compared to those prepared from chemically modified fibre. The efficiency of the modification was determined through titration method to determine the epoxide content of epoxy resin, viscosity measurement and FTIR. The effect of APTES modification on various properties of cured castings is studied through differential scanning calorimeter, contact angle measurement and tensile testing. The addition of APTES into the epoxy resin decreased the epoxide content in the resin as evident from the titration method. The tensile strength of cured castings decreased after the resin modification. The tensile strength and elongation at break of the viscose fabric composites prepared from modified resin, increased up to 14 and 41%, respectively. The improved adhesion of APTES-modified epoxy resin to the viscose fibre is confirmed from SEM analysis of tensile fracture surface.acceptedVersionPeer reviewe