The invention relates to compounds of the formulae:processes for their preparation, polymers, co polymers or block co polymers containing them or their use as monomers or co monomers in free radical polymerisation and in {TAIL ~ the manufacture} of adhesives, dental composites or {HEAD ~ optical lenses} 
The invention relates to compounds of the formulae : processes for their preparation , polymers , co polymers or block co polymers containing them or their use as monomers or co monomers in free radical polymerisation and in { TAIL ~ the manufacture } of adhesives , dental composites or { HEAD ~ optical lenses }
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