No abstract

The effects of coupling agents on the mechanical, morphological, and water sorption properties of luffa fiber (LF)/polypropylene(PP) composites were studied. In order to enhance the interfacial interactions between the PP matrix and the luffa fiber, three different types of coupling agents, (3-aminopropyl)-triethoxysilane (AS), 3-(trimethoxysilyl)-1-propanethiol (MS), and maleic anhydride grafted polypropylene (MAPP) were used. The PP composites containing 2-15 wt% of LF were prepared in a torque rheometer. The tensile properties of the untreated and treated composites were determined as a function of filler loading. Tensile strength and Young's modulus increased with employment of the coupling agents accompanied by a decrease in water absorption with treatment due to the better adhesion between the fiber and the matrix. The maximum improvement in the mechanical properties was obtained for the MS treated LF composites. The interfacial interactions improved the filler compatibility, mechanical properties, and water resistance of composites. The improvement in the interfacial interaction was also confirmed by the Pukanszky model. Good agreement was obtained between experimental data and the model prediction. Morphological studies demonstrated that better adhesion between the fiber and the matrix was achieved especially for the MS and AS treated LF composites. Atomic force microscope (AFM) studies also showed that the surface roughness of LFs decreased with the employment of silane-coupling agents. q

No abstract

The thermal degradation and flammability of intumescent fire-retardant polypropylene matrix composites consisting of ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonisation agent and natural zeolite (clinoptilolite rich, Go¨rdes II) as a synergistic agent were examined. APP and PER combinations were examined at different ratios (0.25, 0.33, 0.5, 1, 2, 3, and 4) for optimisation of the formulation for flame retardancy. The zeolite was incorporated into flame retardant formulation at four different concentrations (1, 2, 5, and 10 wt%) to investigate the synergism between the flame retardant materials. The thermal degradation and flammability of composites were characterized by thermogravimetric analysis (TGA) and by limiting oxygen index (LOI) measurement and horizontal burning (HB) tests. A synergistic effect in flame retardancy was observed when natural zeolites were used in combination with APP and PER.

An intumescent system consisting of ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonific agent and natural zeolite (clinoptilolite, Go¨rdes II) as a synergistic agent was used in this study to enhance flame retardancy of polypropylene (FR-PP). Zeolite was incorporated into flame retardant formulation at four different concentrations (1, 2, 5, and 10 wt%) to investigate synergism with the flame retardant materials. Filler content was fixed at 30 wt% of total amounts of flame retardant PP composites. Zeolite and APP were treated with two different coupling agents namely, 3-(trimethoxysilyl)-1-propanethiol and (3-aminopropyl)-triethoxysilane for investigation of the influence of surface treatments on mechanical properties and flame retardant performance of composites. Maleic anhydride grafted polypropylene (MAPP) was used for making polypropylene hydrophilic. Flammability of FR-PP composites was measured by the determination of limiting oxygen index (LOI). The LOI values reached to a maximum value of 41% for mercapto silane treated APP:PER (2:1) PP composite containing 5 wt% zeolite. The tensile strength of composites was increased by the addition of MAPP and elongation at break of composites was increased with silane treatments.

No abstract

a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / i j r e f r i g i n t e r n a t i o n a l j o u r n a l o f r e f r i g e r a t i o n 3 3 ( 2 0 1 0 ) 7 1 4 -7 2 0 0140-7007/$ -see front matter ª

No abstract