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Jūrmala, Latvia

Kajaks J.,Riga Technical University | Kalnins K.,Riga Technical University | Uzulis S.,MNKC SIA | Matvejs J.,MNKC SIA
Central European Journal of Engineering | Year: 2014

Wood polymer composites (WPC) are widely used materials in different industries because of many application, processing and recycling advantages compared to traditional thermoplastic polymer composites containing mineral fillers [1]. However, the commercial success of these materials primarily depends on improvements in moisture performance, and ability to use recycled and waste material as a wood filler. The research regarding WPC is focused on the chemical interaction between dissimilar material components with an aim to provide strong adhesion to the surface of wood filler-polymer matrix [2]. The goal of this paper was to present results of investigations of exploitation properties of composites containing different plywood production industry byproducts and polypropylene. It was shown that modification of all composites with coupling agent maleated polypropylene (MAPP) considerably improve physical mechanical properties (tensile, flexural, impact strength) of WPC. MAPP (5 wt.%) additions also significantly improve water resistance of WPC. SEM investigations confirmed positive action of interfacial modifiers on strengthening of adhesion interaction between components wood and PP matrix that give considerable increase of exploitation properties of the WPC. © Versita sp. z o.o. Source


Kajaks J.,Riga Technical University | Kalnins K.,Riga Technical University | Uzulis S.,MNKC SIA | Matvejs J.,MNKC SIA
Open Engineering | Year: 2015

During the last 20-30 years many researchers have paid attention to the studies of properties of thewood polymer composites (WPC). A lot of works are closely related to investigations of exploitation properties of wood fibres or wood flour containing polyolefine composites [1, 2]. The most useful from wide selection of polyolefines are polypropylenes, but timber industry waste materials comprising lignocellulose fibres are often used as reinforcement of WPC [3-12]. Plywood industry is not an exception - part of waste materials (by-products) are used for heat energy, i.e. burned. In this work we have approbated reinforcing of polypropylene (PP) with one of the plywood industry by-products, such as birch plywood sawdust (PSWD),which containswood fibre fractions with different length [13]. The main fraction (50%) includes fibres with length l = 0.5 - 1 mm. Our previous study [13] has confirmed that PSWD is a promising filler for PP reinforcing. Addition of PSWD up to 40-50 wt.% has increased WPC tensile and flexural modulus, but decreased deformation ability of PP matrix, impact strength, water resistance and fluidity of composite melts. It was shown [13] that modification of the composites with interfacial modifier - coupling agent maleated polypropylene (MAPP content up to 5-7 wt.%) considerably improved all the abovementioned properties. SEM investigations also confirmed positive action of coupling agent on strengthening of adhesion interaction between components wood and PP matrix. Another way how to make better properties of the WPC is to form hybridcomposites [1, 14-24]. Very popular WPC modifiers are nanoparticle additions like organonanoclays, which increase WPC physical-mechanical properties - microhardness, water resistance and diminish barrier properties and combustibility [1, 2, 14-17, 19, 20]. The goal of this study was to investigate organonanoclays influence on plywood production industry by-product birch plywood sawdust (PSWD) containing polypropylenewood hybrid composites (WPHC) physical-mechanical and other exploitation properties. © 2015 J. Kajaks et al. Source

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