Hydrophihc plastic

Chemical reactivity Although the use of bases with low hydroxyl values (low partial ester content) is indicated to minimize the risk of interaction with chemically reactive compounds, formulators should be aware that hydroxyl values are also related to hydrophihc properties, which, in turn, can modify both release and absorption rates. Bases with low hydroxyl values tend to be less plastic than those with higher values and, if cooled rapidly, may become excessively brittle. Peroxide values give a measure of the resistance of the base to oxidation and are a guide to the onset of rancidity. 

Hydrophihc polymers such as nylon or the ceUulosic plastics wih absorb relatively large amounts of water. This could cause dimension stabihty problems or processing problems. It could also lead to hydrophihc degradation in certain polymers such as polyester-based urethanes. On prolonged exposure to high humidity and high temperatures, these polymers wih revert back to a hquid state through hydrolysis. 

All natural fibers are hydrophihc and their moisture content ranges from 3 to 13%. This leads to a very poor interface between natural fiber and the hydrophobic matrix and very poor moisture resistance. Several fiber surface treatments are used to improve the interface viz-thermal treatment, chemical treatment, and use of coupling agents (Bledzki and Gassan, 1999). Fillers are added to composites for technical and chemical reasons (Milewski and Katz, 1980). Calcium carbonate has maximum usage as filler in plastics and FRP due to its low cost, non-toxicity and lack of odor. Present work gives effectiveness of jute fabric treatment and addition of filler on properties of jute reinforced polyester composites (JFRP). 

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