Polyamide 6–wheat straw composites: Effects of additives on physical and mechanical properties of the composite

Polyamide 6 was modified with lithium chloride (LiCl) salt and N-butyl benzenesulfonamide (N-BBSA) plasticizer (additives). The modification was done in order to develop an environmentally friendly composite, composed of wheat straw (WS). A 15 wt% of ground WS was compounded with Polyamide 6 along with the additives. Addition of LiCl decreased the melting point of the matrix, allowing for a lower compounding temperature. However, a pseudo-crosslinking formation upon addition of salt limited the polymer chain movement and restricted the processing temperature. LiCl addition increased the tensile and flexural modulus of the composite, but decreased the tensile and flexural strength. Decrease in the strength was found to be related to the increase in the residence time of material during extrusion causing severe WS thermal degradation. Addition of N-BBSA eased the processing due to lubrication effect, however, when used in excess, lowered the flexural modulus and strength. Addition of WS to Polyamide 6 increased the modulus of the matrix. Matrix tensile modulus and flexural modulus were enhanced by 27%; however, a decrease in strength of the matrix was obtained. Addition of WS, LiCl, and plasticizer lowered the impact properties of Polyamide 6. It was concluded that combination of 2 wt% LiCl and of 2 wt% N-BBSA gives the best mechanical properties. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

[1]  R. Krishnaprasad,et al.  Mechanical and Thermal Properties of Bamboo Microfibril Reinforced Polyhydroxybutyrate Biocomposites , 2009 .

[2]  L. Visconte,et al.  Mechanical, Thermal and Morphological Characterization of High-Density Polyethylene and Vermiculate Composites , 2009 .

[3]  M. Sain,et al.  Commercialization of Wheat Straw as Reinforcing Filler for Commodity Thermoplastics , 2009 .

[4]  M. Paoli,et al.  Polyamide-6/vegetal fiber composite prepared by extrusion and injection molding , 2007 .

[5]  A. Sanadi,et al.  Instrumented Impact Testing of Kenaf Fiber Reinforced Polypropylene Composites: Effects of Temperature and Composition , 2007 .

[6]  Xianbo Huang,et al.  Effect of Intermolecular Interactions and Cooling Rates on Crystallization Behaviors of Polyamide 6 Blends , 2007 .

[7]  M Sain,et al.  Preparation and characterization of wheat straw fibers for reinforcing application in injection molded thermoplastic composites. , 2006, Bioresource technology.

[8]  Mohini Sain,et al.  Interface Modification and Mechanical Properties of Natural Fiber-Polyolefin Composite Products , 2005 .

[9]  G. Michler,et al.  Deformation mechanisms and mechanical properties of modified polypropylene/wood fiber composites , 2004 .

[10]  C. Azhari,et al.  Thermal and flow property–morphology relationship of sugarcane bagasse fiber-filled polyamide 6 blends , 2004 .

[11]  Z. Stachurski,et al.  Composite materials based on wood and nylon fibre , 2003 .

[12]  A. Tonelli,et al.  Manipulation of Nylon-6 Crystal Structures with Its α-Cyclodextrin Inclusion Complex , 2002 .

[13]  P. R. Lewis.  Failure of Plastics and Rubber Products: Causes, Effects and Case Studies Involving Degradation , 2001 .

[14]  D. M. Lincoln,et al.  Temperature dependence of polymer crystalline morphology in nylon 6/montmorillonite nanocomposites , 2001 .

[15]  Hsu-Chiang Kuan,et al.  Mechanical, thermal and morphological properties of glass fiber and carbon fiber reinforced polyamide-6 and polyamide-6/clay nanocomposites , 2001 .

[16]  Tzong‐Ming Wu,et al.  Polymorphism in nylon 6/clay nanocomposites , 2000 .

[17]  S. Weng,et al.  Investigation on the Interaction between Polyamide and Lithium Salts , 2000 .

[18]  K. Wei,et al.  Induced γ → α crystal transformation in blends of polyamide 6 and liquid crystalline copolyester , 2000 .

[19]  Andrzej K. Bledzki,et al.  Properties and modification methods for vegetable fibers for natural fiber composites , 1996 .

[20]  R. Rowell,et al.  Renewable Agricultural Fibers as Reinforcing Fillers in Plastics: Mechanical Properties of Kenaf Fiber-Polypropylene Composites , 1995 .

[21]  L. Goldfarb.  Transcrystallization of isotactic polypropylene , 1980 .

[22]  D. Acierno,et al.  Bulk properties of synthetic polymer-inorganic salt systems. V. Mechanical properties of oriented poly(caproamide) , 1979 .

[23]  D. Gray.  Polypropylene transcrystallization at the surface of cellulose fibers , 1974 .