Effect of maleated polypropylene as coupling agent for polypropylene composites reinforced with hemp strands

Mutjé, Pere; Vallejos, María Evangelina; Gironès, Jordi; Vilaseca, Fabiola; López, Antonio Fernández; López, Joan Pere; Méndez, José Alberto

doi:10.1002/app.24315

Cited by 111 publications

(76 citation statements)

References 29 publications

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“…Polypropylene is a polymer material based on aliphatic CH-CH 2 -(CH 3 )-structures; such a structure lacks any capacity to interact with polar species such as water or hydroxyl-functionalized reinforcements as cellulosic fibers. The very different chemical structure of cellulosic fibers means that the material has a low compatibility with aliphatic matrices, as has been well explained in the literature (Mutjé et al 2006;Méndez et al 2007). The incompatibility involves the establishment of non-chemical anchored interphases representing a physical path for water diffusion.…”

Section: Water Uptake Behaviormentioning

confidence: 99%

Stone-Ground Wood Pulp-Reinforced Polypropylene Composites: Water Uptake and Thermal Properties

López¹,

Gironès²,

Méndez³

et al. 2012

BioResources

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Two of the drawbacks of using natural-based composites in industrial applications are thermal instability and water uptake capacity. In this work, mechanical wood pulp was used to reinforce polypropylene at a level of 20 to 50 wt. %. Composites were mixed by means of a Brabender internal mixer for both non-coupled and coupled formulations. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to determine the thermal properties of the composites. The water uptake behavior was evaluated by immersion of the composites in water until an equilibrium state was reached. Results of water absorption tests revealed that the amount of water absorption was clearly dependent upon the fiber content. The coupled composites showed lower water absorption compared to the uncoupled composites. The incorporation of mechanical wood pulp into the polypropylene matrix produced a clear nucleating effect by increasing the crystallinity degree of the polymer and also increasing the temperature of polymer degradation. The maximum degradation temperature for stone ground wood pulp-reinforced composites was in the range of 330 to 345 ºC.

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Section: Water Uptake Behaviormentioning

confidence: 99%

Stone-Ground Wood Pulp-Reinforced Polypropylene Composites: Water Uptake and Thermal Properties

López¹,

Gironès²,

Méndez³

et al. 2012

BioResources

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“…Reports in the literature indicate that impact resistance often decreases as an effect of wood reinforcement [38][39][40][41][42][43][44] similarly to many particulate filled composites [45][46][47][48][49][50][51].…”

Section: Fracture Toughnessmentioning

confidence: 99%

Tensile and impact properties of three-component PP/wood/elastomer composites

Keledi

Sudár

Burgstaller³

et al. 2012

Express Polym. Lett.

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Polypropylene (PP) was reinforced with wood flour and impact modified with elastomers to increase stiffness and impact resistance simultaneously. Elastomer content changed in four (0, 5, 10 and 20 wt%), while that of wood content in seven steps, the latter from 0 to 60 wt% in 10 wt% steps. Structure and adhesion were controlled by the addition of functionalized (maleated) polymers. Composites were homogenized in a twin-screw extruder and then injection molded to tensile bars. Fracture resistance was characterized by standard and instrumented impact tests. The results showed that the components are dispersed independently of each other even when a functionalized elastomer is used for impact modification, at least under the conditions of this study. Impact resistance does not change much as a function of wood content in PP/wood composites, but decreases drastically from the very high level of the PP/elastomer blend to almost the same value obtained without impact modifier in the three-component materials. Increasing stiffness and fiber related local deformation processes led to small fracture toughness at large wood content. Micromechanical deformation processes depend mainly on the strength of PP/wood interaction; debonding and pull-out take place at poor adhesion, while fiber fracture dominates when adhesion is strong. Composites with sufficiently large impact resistance cannot be prepared in the usual range of wood contents (50–60 wt%)

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“…The improvement of the elastic moduli is slightly superior to that obtained with particulate fillers [3][4][5][6][7][8][9]. The natural strands as jute, kenaf, flax, are the most effective cellulosic reinforcement fibers [2,[10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…This fact normally results in poor interfacial adhesion and in restricted ability of stress transfer from the matrix to the reinforcement. Therefore, the enhancement of 3 compatibility between the hydrophobic thermoplastic polymer and the hydrophilic natural fibers has attracted much attention of the researchers, and various techniques were evaluated in previous works [15][16][17][18]. Generally speaking, chemical modifications are used to decrease the polarity of the fibers surface in order increase its compatibility with the polymer surface.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the interfacial shears strength, orientation factor and mean equivalent intrinsic tensile strength in old newspaper fiber/polypropylene composites

Serrano

Espinach²,

Julián³

et al. 2013

Composites Part B: Engineering

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 angle and the mean interfacial shear strength. The contributions of the matrix, the subcritical and the supercritical fibers to the tensile strength of the composite material were also computed.

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Effect of maleated polypropylene as coupling agent for polypropylene composites reinforced with hemp strands

Cited by 111 publications

References 29 publications

Stone-Ground Wood Pulp-Reinforced Polypropylene Composites: Water Uptake and Thermal Properties

Stone-Ground Wood Pulp-Reinforced Polypropylene Composites: Water Uptake and Thermal Properties

Tensile and impact properties of three-component PP/wood/elastomer composites

Estimation of the interfacial shears strength, orientation factor and mean equivalent intrinsic tensile strength in old newspaper fiber/polypropylene composites

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