Influence of type and concentration of maleic anhydride grafted polypropylene and impact modifiers on mechanical properties of PP/wood sawdust composites

Abstract

Surface treatments of natural fibers in polymer-wood composites (PWC) are still one of the most interesting subjects for research among technologists, especially with inclusion of other property modifiers in the composites. This work investigated the effects of incorporating different types and contents of maleic anhydride grafted polypropylene (MAPP) and impact modifiers, as property promoters, on the mechanical properties of PP/wood sawdust composites. The concentration of wood sawdust was also varied. The experimental results revealed that increasing the wood fiber into the PP matrix reduced the overall strength and toughness of the composites. It was observed that the higher the impact modifier concentration, the greater the improvement in toughness of the PP/wood composites, and therefore an impact modifier with high comonomer content and high melt flow rate is recommended. This work recommends a MAPP concentration of 2.0 wt % (of sawdust) to be introduced into the PP/wood composites containing 11.1 wt % selected impact modifier, for optimization of the overall composite mechanical strength. The recommended MAPP coupling agent should possess a high wt % MAH-grafting level and high molecular weight of PP copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: [475][476][477][478][479][480][481][482][483][484] 2005

Wood flour filled PP composites: Compatibilization and adhesion

“…Various techniques are used or at least tried for the improvement of 4 interfacial adhesion including the treatment of the wood with sodium hydroxide [4,19,20], coupling with functional silanes [4], or the coating of wood flour with stearic acid [21,22]. However, polymers functionalized with maleic anhydride (MA) or acrylic acid (AA) are introduced the most often into polyolefin composites [2][3][4]17,[19][20][21][22][23][24][25][26][27][28][29][30]. The functional groups of these polymers were shown to interact strongly or even react chemically with the surface of wood [17,24,26], while the long alkyl chains diffuse into the matrix making stress transfer possible.…”

“…molecular weight and degree of functionalization, of the compatibilizer on composite properties is not completely clear. Several authors claim that larger molecular weight and smaller functional group content are more advantageous than the opposite [17,23]. Their conclusions are based on the measurement of tensile strength and interfacial shear strength, but the number of such studies is limited and most of them do not offer a satisfactory explanation for the effect of these factors on composite properties.…”

Madera plástica de polipropileno reforzado con harina de madera: efecto de la adición de agentes compatibilizantes provenientes de recursos renovables

“…Sin embargo, el módulo de flexión da muestra PPr/PIE fue aproximadamente 67% superior al PPr. Este comportamiento esta probablemente asociado al hecho de que las partículas de madera son más rígidas que la matriz polimérica y de esta forma, su adición al PPr causa el aumento de la rigidez del compósito [2,9]. PPr/PIE/PPgAM 44,3 ± 0,9 2271 ± 11 26,7 ± 0,9…”

Production and evaluation of recycled polymers from açaí fibers

“…Reports in the literature show that, in general, the tensile strength of pure PP is higher than that of PP containing natural fibers, except when coupling agents that improve interfacial adhesion and consequently, the tensile mechanical results, are used [24][25][26] . In the present study, the results of the tensile test with the HIPS/açaí fiber composites were in agreement with similar work carried out with HIPS/sisal fibers produced using a similar process, in which the tensile strength at rupture decreased from 21.66 to 11.41 MPa when combined with short sisal fibers at 20% by volume.…”