Lignin Reinforced Rubber Composites

Shukla, M K and Nigam, Vineeta and Singh, Harjeet and Setua, D K and Mathur, G N (1998) Lignin Reinforced Rubber Composites. In: Proceedings of Composite Materials. NML, Jamshedpur, India, Jamshedpur, pp. 233-245.



Lignin is the country's second most abundant renewable biomass resource next to cellulose. The pulp and paper industries produce very large quantities of lignin, most of those are burned to recover energy, pulping chemicals, enzymatic or acid hydrolysis to sugars followed by fermentation to alcohols. Another emerging technology where the lignin being used is in the adhesives and asphalts. For the former, lignin partly replaces phenol in phenol-formaldehyde formulations, for the latter lignin is used as an extender. Lignin in polyurethanes is for good mechanical properties and reactions of lignin such as grafting and crosslinking agent are also well known. Novolak-hexamine based phenolic resins are commonly used as reinforcing and processing aids in nitrile rubber (NBR) compounds. Not only the oil and petrol resistances increase significantly , resin loading is also found to offer better heat resistant properties than carbon blacks. For seals, valves and gasket applications addition of phenolic resins provides superior abrasion resistance, ageing and negligible hardening effects at elevated temperatures. Poor tackiness of NBR compounds can easily be eliminated by using phenolic resin in place of carbon black. The study presented here is to explore the possibility of employing lignin into some value -added rubber based composites . Lignin, gymnosperms, angiosperms and glass varieties, contain alcohol and phenolic groups and also double bonds in their structural moiety and therefore, could resinify into prepolymer in presence of hexamine.Varied proportions of lignin upto 50 parts with respect to total rubber plus hexamine,have been incorporated in medium acrylonitrile (37%) NBR and studied for their processing characteristics and physico-mechanical properties e.g. reinforcement, oil and fuel resistances, ageing and thermal stability. Efficacy of lignin has been found to be superior to either phenolic resin-hexamine or carbon black filled compounds. Finally, attempt has also been made to modify the surface chemistry incorporating CO,> C=O etc. groups by additions of dicumyl peroxide and this modified lignin was found to offer improved rubber-filler adhesion, tackiness and physical properties.

Item Type:Book or NML Publication
Uncontrolled Keywords:Lignin; adhesives & asphalts
Divisions:Material Science and Technology
ID Code:2682
Deposited By:Sahu A K
Deposited On:18 Mar 2011 14:49
Last Modified:06 Jan 2012 12:02
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