each R* is the same or different and is a hydrocarbon or a carboxy or a heteroatom and each R$ or R$$ or R** is the same or different and is an alkyl having one or more carbon atoms or an aryl with the restriction that at least one R$ and at least one R$$ is an alkyl having one or more carbon atoms, Preferably, the peroxide is a linear dialkyl peroxide containing at least two peroxide goups and wh