Abstract: Disclosed herein are a modified guayule resin product and related processes for preparing the modified guayule resin product. The modified guayule resin product comprises a mixture of argentatins having at least one functional group, wherein the at least one functional group is provided by a functionalizing compound selected from alkoxysilanes, mercaptosilanes and blocked mercaptosilanes. In a second embodiment, a process for preparing a modified guayule resin product is provided whereby a guayule resin component (comprising a mixture of argentatins) is mixed with a functionalizing compound selected from alkoxysilanes, mercaptosilanes and blocked mercaptosilanes to produce a modified guayule resin comprising functionalized argentatins having at least one functional group provided by the functionalizing compound.

Abstract: Disclosed herein are methods for improving the rolling resistance of a tire rubber composition by providing a rubber composition including a rubber component which includes a majority by weight of guayule rubber where the guayule rubber includes a bagasse component, and a filler component where the filler component is free of silica, and including at least one silane in the rubber composition, where the at least one silane is selected from the group consisting of mercaptosilanes, blocked mercaptosilanes, and alkoxysilanes. Also disclosed is a tire rubber composition which comprises (a) 100 parts of a rubber component including a majority by weight of guayule rubber where the guayule rubber includes a bagasse component, (b) a filler component, where the filler component is free of silica, and (c) at least one silane selected from the group consisting of mercaptosilanes, blocked mercaptosilanes, and alkoxysilanes.

Abstract: A continuous process for manufacture of a polymer including branched and linear components comprising first polymerizing conjugated diene(s) in the presence of an organometallic initiator to a conversion that is at least 90% complete. A coupling agent is added to obtain a polymer including branched and linear components. The coupling agent is added at a ratio of about 0.3 to about 0.6 coupling equivalents to initiator equivalents.