| Abstract: | Solutions of crystalline, high-melting trans-1,4 polybutadiene (trans-PB), trans-1,4 mix 1,2 butadiene-piperylene copolymer (BPC, low piperylene content), and isotactic trans-1,4 piperylene (trans-PP) were partly hydrochlorinated under mild conditions with gaseous HCl. Glass transition and melting temperatures were strongly affected by the addition of HCl. Several hydrochlorinated trans-PB and -BPC were semicrystalline or amorphous elastomers, susceptible to reversible crystallization when stretched. The straininduced crystallinity was similar to that shown by trans-polybutadiene sequences, particularly in the form that is unstable in bulk at room temperature (form II). The addition of HCl to the asymmetric double bond in trans-PP occurs in a stereoselective way, according to 13C-NMR. under the experimental conditions of the present study the occurrence of side reactions was observed; these reactions decrease the polymer unsaturation to a lower level than that calculated by the amount of HCl added to the polymer. |
