Radiation-induced cross-linking mechanical properties

Another mode of dual curing involves the simultaneous occurrence of free radical and cationic radiation-induced cross-linking polymerization of formulations containing appropriate initiators [20, 23, 28]. This method, which is called hybrid curing, leads to coatings with imique properties. A typical hybrid-cure system contains a diacrylate and a diepoxide, the former polymerizing by a free radical and the latter by a cationic mechanism. Exposure of the system to in-... 

LDPE (100-0)/PP (0-100)/ LlOl RI (0-1) Internal mixer or TSE at 180 °C/torque iheometry/rheology/SEM/mechanical properties/SEC/DSC/DMA/effects of PP-PE viscosity ratios/comparison to radiation induced cross-linking Yu et al. 1990, 1992, 1994... 

Interest in the effects of radiation on polymeric materials is rapidly increasing. Changes in the physical or mechanical properties of a polymer can be induced by small amounts of radiation for example, even a few scissions or cross-links per molecule can dramatically affect the strength or solubility of a polymer. Such changes determine whether a particular polymer will have an application in industry. 

Elastomers are classically blended to improve the physical and mechanical properties of the final material. For example, Dubey et aiP incorporated suitable amounts of EPDM in the SBR matrix because it was expected to impart significant heat and ozone resistance to the SBR matrix. The irradiation-induced vulcanization of SBR/EPDM blends was proved to combine desired properties and high mechanical strength. For example, the formation of a cross-linked network led to a decrease in elongation at break. Cross-linking restricts the movement of the polymer chain against the applied force. Moreover, to decrease the radiation dose (and hence, the cost of radiation), multifunctional acrylates (MFAs) and allylic reactive molecules were used. 

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