Polybenzoxazines (PBz) represents a new class of thermoset polymers based on reaction of aromatic phenol, ammonia/amine and formaldehyde, reagents mainly of petroleum industry origin. There is a need to examine the use of agro based monomers for synthesis of polymeric materials. We reported the solvent-less synthesis of both mono-oxazine and bis-oxazine benzoxazine monomers based on cardanol (waste by-product of cashew-nut tree, Anacardium occidentale), paraformaldehyde with both monoamine1a and bis-amines1b. All the monomers were characterized by 1H-NMR, FTIR spectroscopy and Differential Scanning Calorimetry. Cardanol based PBz resin showed very good thermal stability over petro-based PBz structural analogues.Monofunctional Bz-C based on cardanol, a liquid monomer, showed low Brookfield viscosity (145 mPas at 316K) and good flow behavior. Bz-C was used as a reactive diluent for the solvent-less synthesis of petro-based bisphenol-A benzoxazine.1a We demonstrated a green synthetic route for benzoxazines in one pot � utility of agrochemical waste, no use of solvent for synthesis, partial replacement of phenolic petro-based reagent in one step. The blends of cardanol and bisphenol-A Bz monomers (3:1, 1:1 and 1:3) showed onset of curing (To) in the range 508-484K. To was lowered further using ternary blend with p-hydroxy benzoic acid based Bz.1c;2 Catalytic effect of carboxylic group led to a To of 434K comparable to Phenol-formaldehyde resins. It is expected that synthesis of higher functionality oxazine based on tri-amine and tetra-amine with cardanol will lead to lower the curing temperature without compensating on thermal stability of PBz resins. The effect of structure of amine on synthesized cardanol based PBz resins will be presented.1. Lochab, B.; Varma I. K., Bijwe, J. J. Therm. Anal. Calorimetry, a) 2010,  102, 769-74.b) 2012 , 107, 661-68 c) 2013 , 111, 1357-64.2. Lochab, B.; Varma I. K., Bijwe, J. AMPC, World Congress on Engineering and Technology, Beijing, China, 2012 , 2, 221-25.

Cardanol based benzoxazine polymers:  Structure property correlation

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.