Degradable Rosin-based Polyester Elastomer Synthesis, Characterization And Properties

Rosin is an abundantly available and renewable resource, owing to their characteristic fused ring structure, the hydrophenanthrene moiety of rosin acids is analogous to many aromatic compounds in rigidity, Therefore, rosin and its derivatives have been used as alternatives to petroleum-based aromatic monomers in polymer synthesis, In this study, a series of degradable elastomer derived from natural resource rosin were prepared from acrylopimaric acid (APA), maleic pimaric acid (MPA) adduct of Diels-Alder reaction, then reacted with polyethylene glycol (PEG) and polycaprolactone (PCL), citric acid used as crosslinking agent. The main investigation results are as follows:First, acrylic pimaric acid (APA) and maleic pimaric acid (MPA) were synthesized by reacting natural resource rosin with acrylic acid or maleic anhydride via Diels-Alder reaction, and the reaction condition was also optimized, the yield of each adduct of D-A reaction can be up to 45% and 50% seperately.Second, a series of rosin-based elastomer APA/PEG,APA/PEG/CA were synthesized by reacting rosin-based adduct APA and PEG, CA used as cross-linking agent. The result suggested that rosin-based polyester elastomer synthesized by PEG as soft segment have good thermal stability which T10% of decomposition temperature ranged from 305 to 322℃. Tensile stress ranged from 2.27 to 0.15 MPa and elongation ratio ranged from 125 to 260%. By introducing the hydrophenanthrene moiety of rosin into polyester elastomer, thermal stability and tensile strength could be strengthened, meanwhile, the properties of rosin-based elastomer could be regulated by molar ratio of feedstock and content of cross-linking agent.Third, a series of rosin-based elastomer APA/PCL,MPA/PCL and MPA/PCL/CA were synthesized by reacting rosin-based adduct APA and MPA with PCL, CA used as cross-linking agent. The result suggested that the properties of rosin-based elastomer could be regulated by molar ratio of feedstock and content of cross-linking agent. The thermal stability of rosin-based elastomer synthesized by PCL as soft segment have better thermal stability which T10% was up to 328.5℃, compared with APA/PEG elastomer. Tensile stress was below 0.75 MPa, while elongation ratio was up to 782%. The degradation test of rosin-based polyester elastomer synthesized by PCL as soft segment in PBS solution with aliphatic lipase suggested that the weight loss can up to 33% within four-week time which confirmed that the synthesized polyester elastomer was biodegradable.