Coupling pattern and efficacy of organofunctional silanes in wood flour-filled polypropylene or polyethylene composites

Abstract

The coupling efficacies of four silanes, i.e. n-propyl-trimethoxysilane, g-amino-propyltrimethoxysilane, g-methacryloxypropyl trimethoxy silane, and allyltrimethoxysilane, were investigated in wood flour-filled polypropylene or polyethylene composites. Compared to untreated composites, treatment of wood flour with these silanes alone did not cause any improvement in the mechanical strength of the ensuing composites. In the presence of dicumyl peroxide, composites treated with g-methacryloxypropyl trimethoxy silane and allyltrimethoxysilane exhibited an increase up to 90, 60, and 50% in flexural, tensile, and impact strength, respectively. Moreover, creep deformation was inhibited during the creep recovery test. The improvement was obviously greater in polyethylene-based composites than in polypropylene-based composites. This study demonstrates that the coupling efficacy of silane depends not only on the establishment of covalent bonds between silane and the matrix, but also on the chemical structure of the matrix.

Quantifying effects of compositional variations on microstructural properties of polypropylene-wood fiber composites by melt rheology and tensile test data

“…Using of several additives and various formulation and/or processing attempts have been extensively studied so far to increase interfacial adhesion between components of WPCs. 3–15 Maleic anhydride grafted polyolefins (PE-g-MA, PP-g-MA, etc.) appear to be the most effective compatibilizers or coupling agents for WPCs.…”

Reactivity of Waterlogged Archeological Elm Wood with Organosilicon Compounds Applied as Wood Consolidants: 2D 1H–13C Solution-State NMR Studies

“…Although it has already been confirmed that various silanes can react with cellulose [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ], lignin [ 33 , 34 , 35 , 36 , 37 , 38 ], and wood [ 39 , 40 , 41 , 42 , 43 ], and the results of our previous FT-IR analyses on waterlogged wood treated with organosilicons confirmed the formation of new chemical bonds between them [ 15 , 43 ], the details of the interactions and potential preferences of silanes to react with individual wood polymers remain not fully understood. Therefore, to unveil the mechanism of waterlogged wood stabilization by organosilicon compounds, further research is necessary that will help to better understand the wood–silane interactions, especially in highly decayed wood where the usual cellulose/lignin ratio and the regular chemical composition and structure of wood polymers are altered by degradation processes.…”