e g styrene u03b1 methylstyrene and ethylstyrene a crosslinker is a monomer containing at least two polymerizable carbon carbon double bonds including e g divinylaromatic compounds di and tri meth acrylate compounds and divinyl ether compounds preferably the crosslinker s is a divinylaromatic crosslinker e g divinylbenzene in one embodiment a styrene polymer is made from a mixture of monomers that is at least 75 styrene and divinylaromatic crosslinkers more preferably at least 90 styrene and divinylaromatic crosslinkers and most preferably from a mixture of monomers that consists essentially of styrene and at least one divinylaromatic crosslinker in another embodiment a styrene polymer is made from a monomer mixture consisting essentially of at least one divinylaromatic crosslinker the term u201c acrylic polymer u201d indicates a copolymer formed from a mixture of vinyl monomers containing at least one meth acrylic acid or ester along with at least one crosslinker wherein the combined weight of the meth acrylic acid s or ester s and the crosslinker s is at least 50 weight percent of the total monomer weight preferably at least 75 more preferably at least 90 and most preferably from a mixture of monomers that consists essentially of at least one meth acrylic acid or ester and at least one crosslinker the term u201c phenolic resin u201d indicates a crosslinked copolymer formed from an aliphatic aldehyde or ketone e g formaldehyde and phenol or a substituted phenol or other aromatic compound wherein the weight of phenol or substituted.