Crosslinking property of an oligomeric unsaturated phosphoester used as a potential injectable biomaterial

An unsaturated polyphosphoester (UPPE) that has double bonds in repeatable units could crosslink with a vinyl monomer. A study of how the crosslinking temperature, setting time and mechanical properties are affected by the UPPE molecular weight, N-vinyl pyrrolidinone (NVP)/UPPE ratio and benzoyl peroxide (BPO)/UPPE ratio was conducted. The results of the study indicated that the maximum crosslinking temperature is between 41.1 degrees C and 82.3 degrees C, which is lower than the 97 degrees C of poly(methyl methacrylate) bone cement. The BPO concentration strongly affected the maximum temperature and setting time. High concentration of BPO gives a rapid polymerization rate, causing reaction heat to be released immediately. The compressive strength and compressive modulus will be enhanced with an increase in the NVP/UPPE ratio, the UPPE molecular weight and the BPO concentration. For all formulations, the compressive strength values are between 3.3 MPa and 11.0 MPa and the compressive modulus values are between 4.9 MPa and 101.9 MPa. These initial studies suggest that UPPE is one kind of potential injectable bone tissue engineering scaffold material.