Polymerization kinetics of poly(p-phenylene-cis-benzobisoxazole)

Roitman, Daniel B.; Tung, L. H.; Serrano, Melissa Köhn; Wessling, Ritchie A.; Pierini, P.

doi:10.1021/ma00067a048

Cited by 12 publications

(8 citation statements)

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“…Cis-PBO (intrinsic viscosity [ 771 = 30 dL/g) was synthesized in the nematic phase [ 14 wt % cis-PBO concentration in polyphosphoric acid (PPA) 1 as described by Wolfe l6 and ref. 17. Samples from the polymerization solution were shaped into sheets (typically 1-1.5 mm thick) by pressing the polymerization solutions between two sheets of Teflon@ at ca.…”

Section: Methods a N D Materialsmentioning

confidence: 96%

Protonation of CIS‐PBO in metanesulfonic acid solutions

Roitman

McAlister

McAdon

et al. 1994

J Polym Sci B Polym Phys

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A comparative study of the conductivity behavior of methane‐sulfonic acid solutions of poly(p‐phenylene‐cis‐benzobisoxazole) or cis‐PBO and other compounds, including CH3SO3Na (NaMSA), a cis‐PBO model compound, and 6,7‐dimethyl‐2,3‐di(2‐pyridyl) quinoxaline, a molecule containing four protonating sites, was carried out to determine the degree of protonation of PBO and its model compound. The conductivity dependence with increasing cis‐PBO concentration indicates that only two sites per repeat unit are protonated. © 1994 John Wiley & Sons, Inc.

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Section: Methods a N D Materialsmentioning

confidence: 96%

Protonation of CIS‐PBO in metanesulfonic acid solutions

Roitman

McAlister

McAdon

et al. 1994

J Polym Sci B Polym Phys

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“…The investigation of polymerization kinetics has been conducted by several groups,15,31–33 but it is difficult to draw an unanimous conclusion from these works due to the complexity of the reaction system involving an isotropic‐nematic phase transition. The polymerization rate for PBO was found to decrease sharply with the increase of the molecular weight in the isotropic state,16 which implied a diffusion‐controlled polymerization process.…”

Section: Synthesismentioning

confidence: 99%

“…The polymerization rate for PBO was found to decrease sharply with the increase of the molecular weight in the isotropic state,16 which implied a diffusion‐controlled polymerization process. However, the polymerization in the nematic phase appeared to be independent of the degree of polymerization 33. This result suggests that for well‐mixed reaction mixtures, translational diffusion does not appear to control the polymerization rates of PBO in the nematic phase.…”

Section: Synthesismentioning

confidence: 99%

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

Hu¹,

Jenkins

Min

et al. 2003

Macro Materials & Eng

174

105

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Synthesis, structure, and properties of rigid‐rod polymers with special emphasis on poly(p‐phenylene benzobisoxazole) (PBO) and poly(p‐phenylene benzobisthiazole) (PBZT) have been reviewed. Recent studies on chemical modifications and molecular simulations have also been given. After nearly 20 years of research and development, PBO fiber was commercialized in the late 1990s. However, due to processing difficulties, the concept of the so called molecular composites has not been successful. Development of the high compressive strength M5 and dihydroxy‐PBI fibers clearly suggest that there is potential for further developing properties of this class of materials. Opto‐electronic properties have also been reviewed.Synthesis of PBZT.magnified imageSynthesis of PBZT.

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“…Most previous studies of polymerization kinetics of rodlike molecules report slowing of the polymerization reaction due to diffusion control (Bair et al, 1977;Cotts and Berry, 1981;Jingsheng et al, 1981;Dvornic et al, 1993). An exception is the study of Roitman et al (1993) carried out under high shearing in the neumatic phase in which the rate of polymerization was nearly constant throughout the reaction. Another common feature of the polymerization of rodlike molecules is the existence of an optimal monomer concentration at which the highest molecular-weight polymer is obtained (Bair et al, 1977;Jingsheng et al, 1981;Dvornic et al, 1993).…”

Section: Introductionmentioning

confidence: 99%