Patent ID: 6013774
Filing Date: 2000-01-11
Classification: C08H,C08L,Y10S

Abstract:
A method for preparing a biodegradable composite which includes(i) a material containing grafted lignin having repeat monomer units, R.sub.u, grafted to the lignin and(ii) a polymer,both the grafted lignin and the polymer being biodegradable, comprising:a) free radically graft copolymerizing a substituted ethene or ethyne polymerizable by free radical polymerization on lignin by connecting a carbon atom of substituted ethene or ethyne to a carbon atom of the lignin aromatic ring or to a carbon bonded by one or more carbon bonds to the aromatic ring to thereby form the material containing the grafted lignin having repeat monomer units, R.sub.u, grafted to a backbone of lignin, the substituted ethene being selected from the group consisting of ##STR20## and mixtures thereof where R.sub.1 through R.sub.7 each designate an organic or inorganic functional group which does not interfere with free radical polymerization and is selected from the group consisting of:(1) hydrogen;(2) a halogen;(3) the group consisting of an organic acid, an organic alcohol, an aldehyde, an alkane, an alkene, an alkyne, an amide, an aromatic, a cycloalkane, an ester, an ether, an organic halogen, a ketone, an organic nitrile, a phenol, an organophosphate, and an organic sulfonic acid;(4) the group specified at (3) substituted in at least one carbon atom by a heteroatom with the atomic symbol S, Se, Te, N, P, As, Sb, Bi, Si, Ge, Sn, Pb, or B; and(5) the groups specified at (3) and (4) further substituted by members of the groups specified at (3) and (4),and the polymer is a macromolecule containing 25 to 500,000 repeat units connected one to another; and thenb) mixing the material containing the grafted lignin with the polymer both the material containing the grafted lignin and the polymer thereby becoming biodegradable; the polymer being at least one selected from the group consisting of: main-chain acyclic, carbon polymers; main-chain carbocyclic polymers; main-chain acyclic, heteroatom polymers with --C--O--C-- bonding; main-chain acyclic, heteroatom polymers with --C--S--C-- and --C--S--N-- bonding; main-chain acyclic, heteroatom polymers with --C--N--C-- bonding; main-chain heterocyclic polymers; and formaldehyde resins.