Low molar mass polybutadiene made crosslinkable by silane moities introduced via addition of thiol to double bond: 4. Crosslinking study

• Published in: Polymer (Guilford) Vol. 41; no. 1; pp. 17 - 25
• Main Authors: Schapman, F., Couvercelle, J.P., Bunel, C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2000; Elsevier
• Subjects: Applied sciences; Chemical reactions and properties; Crosslinking; Crosslinking, vulcanization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polybutadiene; Silane; Crosslinking; Polybutadiene; Silane; Catalytic reaction; Thiol; Telechelic polymer; Organic silane; Experimental study; Property processing relationship; Reaction rate; Chemical modification; Dynamic mechanical properties; Crosslinked polymer; Reaction time; Sulfur containing polymer; Butadiene(hydroxy) polymer; Silicon polymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/S0032-3861(99)00133-0

The effect of the number of triethoxy silane functions introduced onto low molar mass hydroxy telechelic polybutadiene was investigated by using swelling measurements and mechanical properties (storage modulus E′ at the rubbery plateau and maximum of tanδ). These triethoxy silane functions were distributed all along the polymer chain by the addition of mercapto propyl triethoxy silanes to vinyl double bonds. Influence of catalyst, temperature, moisture and time were studied. The best experimental conditions correspond to 80°C under moisture with dibutyl tin dilaurate as catalyst. A large increase in Tg (from −70 to −20°C) and E′ (6.5–130MPa) was observed from 1.05 to 7.9 triethoxy silane groups per chain. These results are due to a decrease of the average molar mass per crosslinked unit (Mc) which was not observed when the modification was performed essentially at chain extremities (hydroxy functions) via urethane linkage.