Thermally Induced Cross-Linking and Degradation Reactions of Benzocyclobutene-Based Polymers

Abstract

We describe the use of MALDI-TOF mass spectrometry and collision-induced dissociation (CID) fragmentation techniques to examine the thermally induced cross-linking chemistry of dibenzocyclobutene (BCB) 2 − resorcinol-based materials. The overall goal was to gain a better understanding of benzocyclobutene ring-opening and the subsequent Diels−Alder cycloaddition reactions, which could assist in troubleshooting problems associated with unwanted side-product formation in these materials. Experimental results indicate that relative changes in average molecular mass (e.g., M n ) and signature side-product formation can be used to predict the optimum curing temperature used for cross-linking/polymerization. CID fragmentation studies identified two low kinetic energy degradation pathways for the BCB 2 −resorcinol-based oligomers examined in this study: (1) ether bond cleavage with an associated 1,3-hydrogen transfer and (2) transannular bond cleavage across the cyclooctadiene linkage. This information was used to develop a general fragmentation model for BCB 2 −resorcinol-based materials to predict their degradation products and verify their chemical connectivity.

Biorenewable rosin derived benzocyclobutene resin: a thermosetting material with good hydrophobicity and low dielectric constant

“…[1][2][3][4][5] The monomer benzocyclobutene, in certain circumstances, could undergo ring-opening reaction to provide reactive o-quinodimethane, which could undergo dimerization and polymerization, or react with a dienophile to form a Diels-Alder adduct. 1,3,4,[6][7][8][9][10][11] Generally, the resulting benzocyclobutene resins show excellent dielectric properties and thermal stability, and low water absorption and thermal expansion coefficient. 12 Correspondingly, the benzocyclobutene resins have been widely used in the elds of aerospace, electronics and microelectronics, as enameled wire varnish, large scale integrated circuits, composite materials, etc.…”

Sequencing of Side-Chain Liquid Crystalline Copolymers by Matrix-Assisted Laser Desorption/Ionization Tandem Mass Spectrometry

“…The matrix and cationizing agent solutions were mixed in the ratio 10:1 ( v / v ), and approximately 0.5–1.0 μL of the resulting mixture were spotted onto a 384-well ground steel MALDI target plate and allowed to dry under ambient conditions; 0.5–1.0 μL of sample solution was then deposited on top of the dried matrix/salt spot, followed by an additional 0.5–1.0 μL of matrix/salt solution on top of the dried sample spot (sandwich method) [26]. MS/MS experiments were performed using the instrument’s LIFT (laser-induced fragmentation) mode [26,27] with no additional collision gas [28]. Bruker’s FlexAnalysis software was used for data analysis.…”

Characterization of microstructures and reaction mechanisms of Tröger's base polymers of intrinsic microporosity

“…ESI requires solubility, and conventional MALDI and direct laser desorption methods have only been marginally successful for intractable polymers . However, the evaporative‐grinding (E‐G) MALDI sample preparation method was developed to overcome solubility problems, and will be our analysis technique of choice for the present study of Tröger's base PIMs.…”

“…This report serves as an update on new developments and applications of the E‐G MALDI sample preparation method, combined with collision‐induced dissociation (CID) fragmentation, for improved rapid microstructure characterization of poorly soluble/insoluble Tröger's base PIMs . Examples will be presented of the use of enhanced data mining with ultrahigh‐resolution MS and statistical analysis for examining the various distributions in molecular mass, chemical connectivity, and end groups generated during synthesis of Tröger's base PIMs.…”