MALDI–TOF/TOF CID Study of Polycarbodiimide Branching Reactions

Gies, Anthony P.; Heath, William H.; Keaton, Richard J.; Jimenez, Jorge; Zupancic, Joseph J.

doi:10.1021/ma401481g

Cited by 13 publications

(6 citation statements)

References 19 publications

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“…A more plausible explanation would be catalyst-induced guanidine branch formation. Such reactions have already been reported as known side products in carbodiimides made from MDI. , Since these species exclusively appear in the iron(III) reacted PMDI, these results indicate that iron(III) is catalyzing the formation of branched carbodiimides.…”

Section: Resultssupporting

confidence: 69%

Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

et al. 2016

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The overall goal of the present study was to identify the high molecular weight species formed during the synthesis and processing of polymeric methylene diphenyl diisocyanate (PMDI) and determine the root cause of the viscosity buildup in these materials. Initial studies focused on the use of MALDI-TOF mass spectrometry to examine the PMDI mixture and MALDI-TOF/TOF CID fragmentation for elucidating the degradation mechanisms of the identified compounds. The low molecular mass portion of the MALDI spectrum was observed to contain the expected PMDI and small quantities of carbodiimides (CDIs). The high molecular mass portion of the spectrum primarily contained 1,3-diazetidine branched carbodiimide dimers, uretonimine branched CDIs, and imino-s-triazine along with low levels of guanidine branched CDIs. The results of this study indicate that the root cause of the observed CDI defects was extensive branch formation through unexpected side reactions catalyzed by iron(III). These reactions lead to a buildup of viscosity which poses a significant challenge during the processing of these materials.

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Section: Resultssupporting

confidence: 69%

Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

et al. 2016

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“…The molecular ion peaks are all labelled in the (x:y)Z format, where x = the number of CC1 for the reactive product precursors, y = the number of CN1 for the reactive product precursors, Z = the species of cation ions. And it is important to stress that the polymer M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT fragment ions depends primarily on the extent of precursors ion "breakage" caused by collision impact with gas and the cation ions such as Na + , which widely exist in the nature world [41][42][43][44][45]. m55-15, 30, 60 and m55&20wt%DPPH-15, 30, 60 are presented in Fig.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Systematic study on highly efficient Thermal Synergistic Polymerization effect between alicyclic imide moiety and phthalonitrile: Scope, Properties and Mechanism

Ping

et al. 2016

Polymer

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“…Moreover, the theoretical calculated and the actual measured molecular weights of the different oligomers are shown in Table , where x is the degree of polymerization and y is the type of cation. And it should be noted that the polymer fragment ions depends primarily on the extent of precursors ion “breakage” caused by collision impact with gas and the cation ions such as H + , Li + , and Na + , which widely exist in nature . Fragment ions of dimer, trimer, pentamer, and hexamer all can be found from the MALDI–TOF MS spectra, which further prove that the products are probably linked by the isoindoline unit …”

Section: Resultsmentioning

confidence: 83%

New model phthalonitrile resin system based on self‐promoted curing reaction for exploring the mechanism of radical promoted‐polymerization effect

Liu

Peng

et al. 2019

J of Applied Polymer Sci

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The reaction mechanism and product properties of radical promoted-polymerization effect of phthalonitrile (PN) were further studied in this article. Different from the previous blending model system, this work provided a structurally symmetrical self-promoted PN model compound [di-imide PN model monomer (DAIM-PN)], which was more conductive to study the polymerization mechanism. Combination of "in situ" infrared, proton nuclear magnetic resonance, and matrix-assisted laser desorption/ionization time of flight mass spectrometry offered a clearer picture of polymerization mechanism. The results indicated that DAIM-PN formed isoindoline and its cyclized tetramer of phthalocyanine selectively during the curing process. This work also demonstrated that the aliphatic chain participated in the reaction of nitrile group and provided more evidence for the reaction site (secondary carbon). Besides, high performance polymers with good processing properties, excellent thermal stability (overall char yield >74% at 800 C, N 2 ), and heat resistance (T g > 470 C) were obtained by blending and copolymerizing DAIM-PN with 1,3-bis(3,4-dicyanophenoxy)benzene. The effectiveness and application potential of the reaction mechanism were confirmed.Our recent work has indicated that the alicyclic mono-imide moiety (MAIM) could promote the polymerization and simplify the reaction path of PN [1,3-bis(3,4-dicyanophenoxy)benzene (3BOCN)] by the radical process. [34][35][36][37] The product structures of radical promoted-polymerization effect were mainly composed of isoindoline, minor phthalocyanine, which was different with traditional curing systems, since there was no triazine formed, and Additional Supporting Information may be found in the online version of this article.

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MALDI–TOF/TOF CID Study of Polycarbodiimide Branching Reactions

Cited by 13 publications

References 19 publications

Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

Iron(III)-Catalyzed Chain Growth Reactions of Polymeric Methylene Diphenyl Diisocyanate

Systematic study on highly efficient Thermal Synergistic Polymerization effect between alicyclic imide moiety and phthalonitrile: Scope, Properties and Mechanism

New model phthalonitrile resin system based on self‐promoted curing reaction for exploring the mechanism of radical promoted‐polymerization effect

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