Synthesis of aromatic polybenzoxazoles by silylation method and their thermal and mechanical properties

Imai, Yumiko; Itoya, Kazuo; Kakimoto, Masa–aki

doi:10.1002/1521-3935(20001101)201:17<2251::aid-macp2251>3.3.co;2-n

Cited by 11 publications

(15 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this work, the PI-co-PBO nanofibers showed excellent thermal stability and mechanical properties. When the test temperature increased, the strength and modulus decreased, but still much higher than those of PBO films at room temperature as reported in the literatures 28,37,38 and smaller than those of aligned PBO nanofibers at the corresponding temperature. The aligned PI-co-PBO (ANF-450) nanofibers were stretched until break at the temperature of 200, 250, 300, 400 and 450 °C.…”

Section: Thermal Mechanical Properties Of Electrospun Nanofiberssupporting

confidence: 54%

Thermal, mechanical and thermomechanical properties of tough electrospun poly(imide-co-benzoxazole) nanofiber belts

et al. 2015

View full text Add to dashboard Cite

Electrospun PI-co-PBO nanofiber belts possessed superior thermal mechanical properties.Mechanically strong electrospun nanofibers at high temperature are highly desired in aerospace industry, high temperature filtration and fire protection clothing. In the present work, highly tough poly(imide-co-benzoxazole) (PI-co-PBO) nanofiber belts with excellent thermal stability, mechanical properties and thermal mechanical properties were produced from the high viscous methoxy-containing polyamic acid (MeO-PAA) solution by electrospinning followed with thermal rearrangement. The chemical structures of the polymer nanofibers and the corresponding thermal rearrangement were confirmed by 1H-NMR, FT-IR and TGA. The mechanical properties and thermal mechanical properties were characterized by tensile test and thermal mechanical analysis (TMA). The aligned nanofiber belt heat-treated at 450 °C (ANF-450) had the highest tensile strength of 559 MPa, modulus of 11.2 GPa and toughness of 12.0 J g-1, respectively, which were much higher than those of the pure PBO films made by thermal rearrangement. The TMA test showed that the ANF-450 exhibited high tensile strength retention of 90% and modulus retention of 94% at a high temperature of 200 °C. These excellent thermal mechanical properties make electrospun PI-co-PBO nanofibers promising candidates in high temperature areas.

show abstract

Section: Thermal Mechanical Properties Of Electrospun Nanofiberssupporting

confidence: 54%

Thermal, mechanical and thermomechanical properties of tough electrospun poly(imide-co-benzoxazole) nanofiber belts

et al. 2015

View full text Add to dashboard Cite

show abstract

“…According to the weight loss and the similar temperature range, it indicates that the ring-closing reaction of polyamide occurs. [53][54][55] After the ring-closing reaction stage, curve 1 shows a weight loss of thermal decomposition at 620°C similar with the weight loss ( Figure 3C, TGA curve 2) of PBO that transformed in PPA from prepolymer polyamide. TGA curve 2 of PBO demonstrates excellent thermal stability because PBO does not decompose until the temperature is over 620°C.…”

Section: Resultsmentioning

confidence: 79%

“…A 14% weight loss at around 220°C for polyamide (Figure C, TGA curve 1) is observed. According to the weight loss and the similar temperature range, it indicates that the ring‐closing reaction of polyamide occurs . After the ring‐closing reaction stage, curve 1 shows a weight loss of thermal decomposition at 620°C similar with the weight loss (Figure C, TGA curve 2) of PBO that transformed in PPA from prepolymer polyamide.…”

Section: Resultsmentioning

confidence: 99%

Novel synthesis of high‐molecular‐weight prepolymer of poly(p‐phenylene benzoxazole) in ionic liquids

Lian

et al. 2018

Polymers for Advanced Techs

View full text Add to dashboard Cite

Using ionic liquids (ILs) as the reaction solvent for the synthesis of prepolymer polyamide of poly(p‐phenylene benzoxazole) (PBO) was investigated. The optimum condition of prepolymer preparation was determined in ILs. A series of 1,3‐dialkylimidazolium ILs were used to be the reaction media of the polycondensation. The relationship between the molecular weight of prepolymer and the structure of ILs was analysed by changing the structure of the cation and species of anion of ILs. In order to prove the feasibility of the transformation, the prepolymer was used to prepare PBO in polyphosphoric acid media, and the conversion process was analyzed. The spinnability of the PBO solution was explored by the preparation of PBO fibers. The basic mechanical properties of PBO single fiber were tested. In a word, using 1,3‐dialkylimidazolium ILs as the reaction solvents was feasible for the synthesis of high‐molecular‐weight PBO prepolymer, which could be a promising PBO preparation method.

show abstract

“…Then the soluble precursors are converted to PBZT or PBO via a thermal cyclization. The two-step method provides some advantages such as avoidance of corrosive acidic solvents and an increase of processability, but the molecular weight of the resulting polymers is lower than the ones prepared in PPA and methanesulfonic acid (MSA) (43)(44)(45)(46)(47)(48). PBI polymers are also prepared from tetraamines and aromatic dialdehydes (49,50).…”

Section: Synthesismentioning

confidence: 99%

Rigid‐Rod Polymers

Wang¹,

Jiang²,

Adams³

2011

Encyclopedia of Polymer Science and Technology

View full text Add to dashboard Cite

Pursuing high strength and high modulus polymer fibers and novel electrooptical properties have motivated much research activity in rigid‐rod polymers in the past 40 years. In this review, we examine the synthesis, structures, and properties of rigid‐rod polymers with emphasis on polybenzobisoxazoles (PBO), polybenzobisthiazoles (PBZT) and polybenzimidazoles (PBI), beginning with their solution properties, especially lyotropic liquid crystallinity. High performance fibers spun from lyotropic liquid crystalline polyphosphoric acid (PPA) solution are described. The characterization of fiber properties including mechanical, thermal, electrical, and optical properties is summarized. PBO (Zylon) and PIPD (M5) fibers were successfully commercialized in high strength applications such as body armor, ropes, cables, and recreational equipment in the last 10 years, and we discuss the possible causes of rapid degradation of some PBO fibers. The concepts of molecular composites and nanocomposites provide new applications in antiballistic materials, fire protection, athletic equipment, cables, strings, ropes, cordage, sails, multilayer circuits, and catalyst supports. Recently, rigid‐rod polymer films have drawn attention in the electrooptical fields, especially for phosphoric acid (PA)‐doped PBI membranes (Celtec MEAs) in the applications of high temperature fuel cells. Computer simulation has been employed as a powerful tool to predict the properties of the rigid‐rod polymers.

show abstract

Synthesis of aromatic polybenzoxazoles by silylation method and their thermal and mechanical properties

Cited by 11 publications

References 13 publications

Thermal, mechanical and thermomechanical properties of tough electrospun poly(imide-co-benzoxazole) nanofiber belts

Thermal, mechanical and thermomechanical properties of tough electrospun poly(imide-co-benzoxazole) nanofiber belts

Novel synthesis of high‐molecular‐weight prepolymer of poly(p‐phenylene benzoxazole) in ionic liquids

Rigid‐Rod Polymers

Contact Info

Product

Resources

About