Compatibilization of kraft lignin‐polyethylene composites using unreactive compatibilizers

Abstract

ABSTRACT This article presents a novel approach to compatibilize Kraft lignin with polyethylene that involves the use of modified poly (styrene‐co‐ethylene‐co‐butylene‐co‐styrene) (SEBS) as unreactive compatibilizers. As SEBS shows no compatibilizing effect on Kraft lignin‐polyethylene composites, SEBS was functionalized via nitration followed by amination to obtain nitrated (SEBS‐NO 2 ) and aminated (SEBS‐NH 2 ) SEBS. The compatibilizing effects of SEBS derivatives were studied by means of morphological and mechanical analyses. The results show that SEBS‐NO 2 is less effective than SEBS‐NH 2 , the later displaying comparable compatibilizing efficiency to a commercial reactive compatibilizer based on maleated polyethylene. Overall, compatibilization was found to decrease lignin particle size. Addition of SEBS‐NH 2 varying between 1% and 10% improved the tensile strength of composites by up to 96%, elongation at break by up to 64%, and impact strength by up to 48%. Finally, the crystallinity and density of the resulting composites were also studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 41040.