Synthesis and characterization of high molecular weight carboxylated polybutadiene

Abstract

High molecular weight carboxylated polybutadienes (cPBDs) with number‐average molecular weight (Mn) from 98,000 to 200,000 and carboxylic acid (COOH) contents of 0.5–10 mol % were successfully synthesized through hydrocarboxylation of polybutadienes (PBDs) at temperatures of 140–150°C using PdCl2(PPh3)2 and SnCl2 · 2H2O catalysts. At low extents of hydrocarboxylation (COOH < 6 mol %), glass transition temperatures (Tg's) of the resulting cPBDs did not change considerably (<10°C). Significant chain scission and crosslinking was not detected during the chemical modification process. Characterization of the microstructures of cPBDs by FTIR, 13C‐NMR, and Raman spectroscopy showed that the carboxylic groups were incorporated on the pendant (1,2) PBD double bonds as well as the backbone (1,4) double bonds, indicating the hydrocarboxylation reaction did not solely occur at the terminal carbons of the pendant double bonds. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3129–3138, 1999

Polymer-Solid Interface Connectivity and Adhesion: Design of a Bio-Based Pressure Sensitive Adhesive

“…The energy of interaction parameter r, between the polymer and the solid can be expressed using the methods of Gong, r ~ χ φ X φ Y (1.1) where χ is the strength of the X-Y acid-base type interaction. Common wisdom on the science of adhesion suggests that as we increase the number of X-Y acid-based interactions, that the polymer-solid adhesion energy increases as G IC ~ r. However, this is not the case and it has been shown by Gong and Lee et al [6][7][8][9][10][11] that the behavior is as depicted in Figure 2 where maximum values of r* are observed.…”

“…In the first experiment by Gong et al [8], the influence of φ X on G IC at constant φ Y ~ 1 was investigated.…”

“…Thus, when φ X < φ* X , and when φ Y < φ* Y , then adhesive failure occurs at the polymer-solid interfaces and the polymer cleanly debonds from the solid, which is critical for the design of pressure sensitive adhesives (PSA). However, when φ X > φ* X and φ Y >φ* Y , we have shown that failure occurs cohesively at a polymer-polymer interface adjacent to the solid substrate [6][7][8][9][10][11]. Cohesive failure occurs in a depletion layer adjacent to the solid by virtue of the high adsorption of the sticker groups on the surface, as shown by Gong [11].…”

Self-healing materials: a review

“…In a seminal study, Kausch and co-workers [13][14][15] showed that single cracks that were formed at room temperature in fracture mechanics specimens of PMMA could be completely rehealed when the surfaces were rejoined and welded above the glass transition temperature T g . Much work has been done by our group [16][17][18][19][20][21][22][23][24][25] and others to understand the concept of strength development at polymer-polymer interfaces and polymer-solid interfaces [69][70][71][72][73][74][75] in terms of the fundamental dynamics of entangled polymers. Using DeGennes' reptation dynamics and the entanglement percolation model, 17,76 we derived a unified theory for the strength development of polymer-polymer interfaces.…”

“…When a mole fraction of sticker groups f(X) is used to bond the polymer to the surface, an optimal sticker group concentration f*(X) is needed to maximize adhesion while minimizing cohesive failure in the boundary layer adjacent to the solid. [69][70][71][72][73][74][75] When f < f*, adhesive failure dominates, the fracture energy G 1c $ f and the solid separates cleanly from the polymer. When f > f*, cohesive failure occurs in a polymer layer adjacent to the surface and G 1c $ 1/f.…”