Influence of nanoclay on properties of HDPE/wood composites

Abstract

Composites based on high density polyethylene (HDPE), pine flour, and organic clay were made by melt compounding and then injection molding. The influence of clay on crystallization behavior, mechanical properties, water absorption, and thermal stability of HDPE/pine composites was investigated. The HDPE/pine composites containing exfoliated clay were made by a two-step melt compounding procedure with the aid of a maleated polyethylene (MAPE). The use of 2% clay decreased the crystallization temperature (T c ), crystallization rate, and the crystallinity level of the HDPE/pine composites, but did not change the crystalline thickness. When 2% MAPE was added, the crystallization rate increased, but the crystallinity level was further lowered. The flexural and tensile strength of HDPE/ pine composites increased about 20 and 24%, respectively, with addition of 1% clay, but then decreased slightly as the clay content increased to 3%. The tensile modulus and tensile elongation were also increased with the addition of 1% clay. The impact strength was lowered about 7% by 1% clay, but did not decrease further as more clay was added. The MAPE improved the state of dispersion in the composites. Moisture content and thickness swelling of the HDPE/pine composites was reduced by the clay, but the clay did not improve the composite thermal stability.

Influence of Organically Modified Nanoclay on Thermal and Combustion Properties of Bagasse Reinforced HDPE Nanocomposites

“…The incorporation of 2 phc OMMT led to the increase in the flexural strength and modulus about 37 and 29%, respectively. The significant improvement in the flexural properties was related to the large aspect ratio and high interfacial contact area of the nanoparticles [10,[12][13][14][15][16][18][19][20][21][22]. As it can be clearly seen from Fig.…”

“…This increment in the tensile properties was mainly attributed to the reinforcing effect of OMMT with high aspect ratio [10,[12][13][14][15][16]. It was expected that strong interfacial adhesion between polymer matrix and nanoparticles efficiently transferred the stress and improved the mechanical properties [18][19][20][21][22].…”

“…Nowadays, the application of organo-modified montmorillonite (OMMT) as a nano-sized reinforcement in WPCs has been developed. It is evident that the addition of small amount of nanoclay (3-5 wt%) substantially enhance the WPCs performance [10][11][12][13][14][15][16][17][18][19][20][21][22].…”

The thermo-oxidative stability and flammability of wood/polypropylene composites

“…The effective use of wood-based particles as fillers or reinforcements in the thermoplastic polymers requires a fundamental understanding of the stability of the composite materials. The majority of lignocellulosic fillers have low degradation temperatures (*200°C), which make them inadequate for processing with thermoplastics with processing temperatures above 200°C [36][37][38]. Decomposition of wood components, such as cellulose and lignin creates voids inside the composite, causing reduction of the mechanical properties [39].…”

“…In general, it has been shown that in order to estimate the thermo-oxidative stability of the composite materials, it is necessary to take into account the oxidation induction time (OIT) [40][41][42]. OIT values depend on factors such as density, temperature, physical and chemical properties of polymer, type and amount of cellulosic fillers [38]. However, analysis of literature data has revealed many controversies; often the use of the same modifications of the lignocellulose component would bring different results.…”