Capability of thermal field-flow fractionation for analysis of processed natural rubber

Applicability of Thermal field flow fractionation (ThFFF) was investigated for the analysis of masticated natural rubber (NR) adhesives produced by a hot melt mastication process. An optimum ThFFF condition for NR analysis wa s found by using tetrahydrofuran (THF) as a solvent/carrier and a field-pro gramming. Low flowrate (0.3 mL/min) was used to avoid stopping the flow for the sample relaxation. Measured molecular weight distribution was used to monitor degradation of rubber during the mastication process. Rubber sample s collected at three different stages of the mastication process and were a nalyzed by ThFFF. It was found that in an anaerobic process rubber degradat ion occurs at the resin-mixing (compounding) zone as well as in the initial breakdown zone, while in an aerobic process most of degradation occurs at the initial breakdown zone. It was also found that E-beam radiation on NR c auses a slight increase in the NR molecular weight due to the formation of a branched structure.