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Abstract: The preparation of hyperbranched polymers from a unique combination of commercially available A2, B3 and CB1 3-type monomers is presented. Direct melt condensation of aliphatic dicarboxylic acid (A2) to compounds having trihydroxy groups ((B3), triethanolamine) and trihydroxy-monoamino groups ((CB1 3), tris(hydroxymethyl)aminomethane) led to a series of hyperbranched polyesters with amine cores and amide linkages. Because of the monomers availability and simplicity of the synthetic process, hyperbranched poly(ester-amine-amide) (HBPEAA) materials can be readily scaled up. This approach was used to synthesize series of prepolymers with varying degree of branching (DB) and distance between branching points. Taking the advantage of reactivity differences of COOH with the NH2 and OH groups, the hyperbranched polymer with different arrangement of amide linkage along the network was synthesized. The influence of reaction conditions such as monomer compositions, temperature and mode of mixing on the polymerization was examined. The DB of the HBPEAA (0.46–0.63) was dependant on the synthetic route. The HBPEAA exhibited moderate molecular weights as determined by NMR and ESI-MS. Thermogravimetric analysis revealed that the prepolymers exhibit reasonable thermal stability. The synthesized prepolymer was successfully utilized to copolymerize with 40% lignin to form toughened elastomeric materials with tensile strength of 12 MPa, Young''s modulus of 33 MPa and 149% elongation. [Copyright &y& Elsevier]

Abstract: Combined characteristics of hydrogen bonded/cross-linked polymer networks based on lignin motifs have been developed. This new type of polymeric material was prepared from an industrial lignin and a highly branched poly(ester-amine) (HBPEA) obtained by melt polycondensation of 1,1,1-triethanolamine (TEA) and adipic acid (AA). The lignin-HBPEA polymers were shown to be insoluble in common organic solvents and were characterized by FTIR and NMR spectroscopies. Thermo-mechanical measurements showed that melt mixing HBPEA with 40% lignin results in a flexible and tough material (T g; 7.7 °C and E′ 3.5 GPa). The hydrogen bonding recognition was based on various hydroxyl groups in lignin and aliphatic ester groups from HBPEA. The extent of interactions could be controlled by varying the amount of lignin added. These networks were thermally reversible and have highly tunable mechanical properties that were controlled by the extent of interactions. High level of mechanical properties could be achieved through the addition of lignin-poly(ester-amine) covalent cross-links. This study shows that the poly(ester-amine) structure plays an important role in the thermo-mechanical properties. By varying the spacer length between lignin and tertiary amine unit, materials with various thermo-mechanical properties were also obtained from the same parent polymer backbone. [ABSTRACT FROM AUTHOR]