Studies in use of coir fiber in blend of ethylene Propylene diene Rubber and Polypropylene

Thermoplastic elastomers are a special class of polymeric materials that combine the propertiesof thermo plasticity during processing and rubber-like behaviour in service. They can beprocessed in conventional plastic processing equipment, such as twin screw extruders, internalbatch mixers, extruders and injection moulding machine, but exhibit vulcanized rubber likeultimate properties (i.e. long-range reversible extensibility) immediately on cooling.Dynamically vulcanized thermoplastic fibrous composites based on melt processed hybridethylene-propylene diene rubber (EPDM)/maleic anhydride (MA) grafting and polypropylene(PP) with coir fibers were prepared. Coir fiber acts as a nucleating agent for polypropylenecrystallization; they also form physical interlocking between EPDM/Polypropylene blends whichserve the function of compatibalization along with EPDM – g – Maleic anhydride. Results fromRubber Process Analyzer, Mechanical Analysis, Scanning Electron Microscope, DifferentialScanning Calorimetery, reflect upon the microstructure developed during dynamic cross linking.The coir fiber forms well dispersed structures in the EPDM/PP / EPDM-g-MA thermoplasticvulcanizates. The EPDM/PP TPV fiber composites show a matrix-disperse type of morphologyin which the cross linked EPDM particles appear in the form of agglomerates covered by a layerof PP coir fiber composites. This has been assigned to the formation of a coir fiber networkstructure by the layer of coir fiber PP covered EPDM rubber particles

Effect of hydroxyl value of acrylic polyol and type of crosslinkers on the properties of Polyurethane coetings

Acrylic polyol base polyurethane coatings were prepared by reacting polyol with hexamethylene diisocyanate (HDI) base prepolymer. Five different types of acrylic polyol based on their hydroxyl value and two type of HDI prepolymer i.e. HDI biuret and HDI trimer were used as a hardners, for preparation of Polyurethane coating. The effect of hydroxyl value of acrylic polyol on PU coating properties like physical, mechanical and chemical properties were studied. The base and hardners were mixed prior to application of coating in a NCO: OH ratio of 1:1.  It was found that the as hydroxyl value of polyol increases, it forms a hard film due to high cross-linked structure than low hydroxyl value polyol. Also HDI prepolymer with higher functionality gives better coating properties