stablesuppliescoupledwithvariationsinviscosityandmicrobialcontaminationledtoa changetosyntheticorsemisyntheticsubstitutes.Syntheticorsemisyntheticpolymers, whicharechemicallymodifiednaturalpolymers,havebeendevelopedtomatchtheprop- ertiesofgumsandresins.Today,theindustryisdrivenbyaneedofimprovedformula- tions,attainablethroughtheuseofcurrentsyntheticmethodologyandthroughtheunder- standingofthemolecularinteractionsbetweenthepolymersandtheothercomponents ofacareproduct.