useful in the composition of the invention include polymers and copolymers derived from one or more olefinic monomer of the general formula ch 2 u2550 chr 34 wherein r 34 is hydrogen or c 1 18 alkyl examples of such olefinic monomers include propylene ethylene and 1 butene with propylene being generally preferred representative examples of polyolefins derived from such olefinic monomers include polyethylene polypropylene polybutene 1 poly 3 methylbutene poly 4 methylpentene and copolymers of ethylene with propylene 1 butene 1 hexene 1 octene decene 1 4 methyl 1 pentene and 1 octadecene the polyolefin may optionally comprise a copolymer derived from an olefinic monomer and one or more further comonomers that are copolymerizable with the olefinic monomer these comonomers can be present in the polyolefin in an amount in the range from about 1 to 10 wt based on the total weight of polyolefin useful such comonomers include for example vinyl ester monomers such as vinyl acetate vinyl propionate vinyl butyrate vinyl chloroacetate vinyl chloropropionate acrylic and alpha alkyl acrylic acid monomers and their alkyl esters amides and nitriles such as acrylic acid methacrylic acid ethacrylic acid methyl acrylate ethyl acrylate n n dimethyl acrylamide methacrylamide acrylonitrile vinyl aryl monomers such as styrene o methoxystyrene p methoxystyrene and vinyl naphthalene vinyl and vinylidene halide monomers such as vinyl chloride vinylidene chloride and vinylidene bromide alkyl ester monomers of maleic and fumaric acid such as dimethyl maleate and diethyl maleate vinyl alkyl ether monomers such as vinyl.