Characterization of melt-polymerized polycarbonate: preparative fractionation, branching distribution and simulation

Hagenaars, A.; Pesce, JJ; Bailly, Christian; Wolf, B. A.

doi:10.1016/s0032-3861(01)00250-6

Cited by 21 publications

(26 citation statements)

References 17 publications

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“…Although the sample molecular weights in this reference are much lower than those obtained in our experiments, we performed the following simple calculations: The literature data 32 can be correlated to Y = 0.1125M w + 822.5 where Y is the modified concentration of PhSALPhC (in ppm) and M w is from 0.24% to 0.5%. If the correlation is also applied to a higher MW sample (e.g., 340,000 g/mol) as observed in our study (e.g., Figure 1), the calculated branching unit concentration is as large as 3.8%, which is about 16 times the unit concentration in the prepolymer.…”

Section: Resultsmentioning

confidence: 99%

UltraHigh Molecular Weight Nonlinear Polycarbonates Synthesized in Microlayers

Baick

Luciani

et al. 2013

Ind. Eng. Chem. Res.

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Ultrahigh molecular weight bisphenol A polycarbonate (BPAPC) with nonlinear chain structures has been synthesized by solid-state polymerization in microlayers at 230°C. It has been found that the molecular weights of the microlayers of low molecular weight prepolymers with thickness ranging from 5 to 35 μm increased rapidly to ultrahigh molecular weight (300,000−600,000 g/mol) without any discoloration. The amorphous prepolymers exhibited much higher reaction rate than the partially crystallized prepolymers. Although the reactive end group mole ratios of the prepolymers prepared by semibatch melt polycondensation deviated significantly from the stoichiometric value, branching and partial cross-linking reactions have been found to occur to rapidly increase the polymer molecular weight. These nonlinear chain structures observed were due to Fries rearrangement, Kolbe-Schmitt rearrangement reactions, and radical-induced scission/cross-linking reactions. The microstructures of the high molecular weight polymers have been analyzed by 13 C NMR, 1 H NMR, pyrolysis-gas chromatography mass spectrometry, and atomic force microscopy.

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Section: Resultsmentioning

confidence: 99%

UltraHigh Molecular Weight Nonlinear Polycarbonates Synthesized in Microlayers

Baick

Luciani

et al. 2013

Ind. Eng. Chem. Res.

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“…Crosslinked structures can also be formed via radical recombination reactions. A small amount of radical species can be formed from homolytic scission of carbonate groups between the oxygen and carbonyl group in BPAPC at high temperatures and from hydrogen abstraction, which result in methylene radicals on carbonate groups and phenoxy radicals, respectively . The byproduct, phenol, is a known radical scavenger .…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, branched and crosslinked PCs are of interest to industry because they have some new potential applications such as a binder in photoconductors and an optical component in multilayer structures . In a melt polycondensation process of BPAPC, the addition of alkali metal and alkaline compounds to the reaction mixture without using trifunctional branching agents has been reported to induce the formation of a small amount of branched polycarbonates by the thermal rearrangement reaction known as Fries rearrangement reaction, leading to about 0.017–0.043 branching units per chain . If the weight average molecular weight per branch arm is higher than the critical molecular weight for entanglements (e.g., M c = 4000–4800 g mol −1 ), the polymer is called the long‐chain branched polymer .…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of ultra‐high molecular weight bisphenol a polycarbonate synthesized by solid‐state polymerization in amorphous microlayers

Baick

Yang

Ahn

et al. 2014

J of Applied Polymer Sci

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The structure and properties of ultrahigh molecular weight polycarbonate synthesized by solid-state polymerization in micro-layers (SSP m ) are reported. A low molecular weight prepolymer derived from the melt transesterification of bisphenol A and diphenyl carbonate as a starting material was polymerized to highly amorphous and transparent polycarbonate of molecular weight larger than 300,000 g mol 21 in the micro-layers of thickness from 50 nm to 20 mm. It was observed that when the polymerization time in micro-layers was extended beyond conventional reaction time, insoluble polymer fraction increased up to 95%. Through the analysis of both soluble and insoluble polymer fractions of the high molecular weight polycarbonate by 1 H NMR spectroscopy and pyrolysis-gas chromatography mass spectrometry (Py-GC/MS), branches and partially crosslinked structures have been identified. The thermal, mechanical and rheological properties of the ultra-high molecular weight nonlinear polycarbonates synthesized in this study have been measured by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and rheometry. The nonlinear chain structures of the polymer have been found to affect the polymer's thermal stability, mechanical strength, shear thinning effect, and elastic properties.

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“…The GPC profile corresponded to a higher fraction with a chain length of around 80-90, probably resulting from the KolbeSchmitt reaction at a high temperature. 3,10 The PC product has been mentioned previously to comprise A n , B n , and S n , whose microscopic distributions importantly affect product usage. Figure 9 shows the weight fraction distribution of A n , B n , and S n in each case.…”

Section: Resultsmentioning

confidence: 99%

“…Jayakannan and Anilkumar9 performed composition analysis with 1 H‐NMR for investigating the ester–carbonate exchange in the reactive blending of PC and cycloaliphatic polyester. Hagenaars et al10 described the quantification of the hydroxyl end group with 1 H‐NMR. However, they did not describe in detail how the end groups were quantified with 13 C‐NMR.…”

Section: Introductionmentioning

confidence: 99%

Modeling the melt transesterification of polycarbonate

Hsu

Wong

Tseng

2008

J of Applied Polymer Sci

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A mathematical model of the melt transesterification of polycarbonate in a mechanically agitated reactor system without a distillation column is proposed. Penetration theory is applied to the mass-transfer operation of volatile components in both a transesterification reactor and a polymerization reactor by simplification of the flow pattern. The applicability of the proposed model is examined by the comparison of its predictions with experimental data of the collected condensate of volatile components, the end-group ratio, and the weight fraction distribution of the resulting polymer. The end-group ratios have been determined by carbon-13 nuclear magnetic resonance spectroscopy, and the distribution of weight fractions has been measured by gel permeation chromatography. It is shown that the model's predictions are very consistent with the experimental data.

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Characterization of melt-polymerized polycarbonate: preparative fractionation, branching distribution and simulation

Cited by 21 publications

References 17 publications

UltraHigh Molecular Weight Nonlinear Polycarbonates Synthesized in Microlayers

UltraHigh Molecular Weight Nonlinear Polycarbonates Synthesized in Microlayers

Structure and properties of ultra‐high molecular weight bisphenol a polycarbonate synthesized by solid‐state polymerization in amorphous microlayers

Modeling the melt transesterification of polycarbonate

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