Dicyclopentadiene design

Ethylene—Propylene Rubber. Ethylene and propjiene copolymerize to produce a wide range of elastomeric and thermoplastic products. Often a third monomer such dicyclopentadiene, hexadiene, or ethylene norbomene is incorporated at 2—12% into the polymer backbone and leads to the designation ethylene—propylene—diene monomer (EPDM) mbber (see Elastomers, synthetic-ethylene-propylene-diene rubber). The third monomer introduces sites of unsaturation that allow vulcanization by conventional sulfur cures. At high levels of third monomer it is possible to achieve cure rates that are equivalent to conventional mbbers such as SBR and PBD. Ethylene—propylene mbber (EPR) requires peroxide vulcanization. 

The preparation of dicyclopentadienylmagnesium uses a specially designed apparatus in which dicyclopentadiene is depolymerized by heating to 160°C. Cyclopentadiene is carried by a stream of N2 to the top of a vertical borosilicate glass reactor that is filled with Mg turnings and heated to 500°C. Dicyclopentadienylmagnesium (mp 177°C) sublimes to the bottom, where it is collected (yield 80% of reacted cyclopentadiene) ... 

To allow ATH filler loads above 100 phr specially designed fillers are neeessary. Unfortunately, fine fillers have very large surface areas ftat makes wetting quite diffieult even with specific wetting and dispersing additives. However, judicious blending can prepare filler loads up to 300 phr with acceptable viscosities for moulding and pultrusion, for instance, with resins like dicyclopentadiene or modified methyl methacrylates. 

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