Mechanical properties of molecular composites. I. Poly (p-phenylene terephthalamide) anion molecules dispersed in poly(4-vinylpyridine)

Tsou, L.; Sauer, J. A.; Hara, M.

doi:10.1002/(sici)1099-0488(19990815)37:16<2201::aid-polb22>3.0.co;2-a

Cited by 19 publications

(6 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our laboratory, we used ion–dipole interactions to prepare various molecular composites in which a rodlike polymer, an ionically modified form of poly( p ‐phenylene terephthalamide) (PPTA), is dispersed in a matrix of a polar polymer. Some of these composites have been prepared using PPTA anion molecules (generally known as K or Na salts),12–14 as depicted in Figure 1. Others have been prepared using PPTA molecules that possess ionic groups attached to one of the phenylene rings or attached to the end of a short side chain 10, 12.…”

Section: Introductionmentioning

confidence: 99%

Mast cells in Wallerian degeneration: Morphologic and ultrastructural changes

Esposito

Santis

Monteforte

et al. 2002

J of Comparative Neurology

View full text Add to dashboard Cite

The morphologic and ultrastructural changes of mast cells were followed in degenerating distal and regenerating proximal stumps of frog brachial nerve during Wallerian degeneration. Quantitative analysis included determination of both number and size of mast cells. The mast cell response to injury consisted of an early and a late phase. In the early phase, there was an increase in mast cell numbers in the proximal site of the lesion and a release of Alcian blue material consistent with mediator release. This phase of mast cell activation may be related, through the secretion of biogenic agents such as heparin and histamine, to the increase of endoneurial vessel size and vascular permeability, providing access for macrophages and mast cell precursors. The later phase, which peaked at 40 days after transection in the degenerating distal stump, consisted in the degranulation of the mast cells. These mast cells, closely associated with macrophages and degenerating Schwann cells, released secretory granules into the endoneurial microenvironment. These degranulating mast cells, through the released acid hydrolases, may contribute along with macrophages and Schwann cells, to the degradation of myelin debris. At the same time, mast cells appeared filled with granular content in the regenerating proximal segment. Therefore, we suggest that mast cells in peripheral nerves may play an important role in nerve degenerating and regenerating mechanisms through the secretion of diffusible molecules.

show abstract

Section: Introductionmentioning

confidence: 99%

Mast cells in Wallerian degeneration: Morphologic and ultrastructural changes

Esposito

Santis

Monteforte

et al. 2002

J of Comparative Neurology

View full text Add to dashboard Cite

show abstract

“…For instance, poly( p -phenylene terephthalamide) was applied to reinforce nylon or poly(4-vinylpyridine). , Only when the LLCP was lower than its critical concentration (<5 wt %) could a homogeneous phase be obtained with increased glass transition temperatures ( T g ) from 150 to 157 °C. This investigation indicated that the concentration of LLCP reinforcement was crucial for the preparation and performance of composites . Another method to fabricate liquid crystalline polymeric composites was melt blending thermotropic liquid crystalline polymers (TLCPs) with a thermoplastic (e.g., PP, PA) or thermosetting matrix (e.g., epoxy resin). − With an increase in the amount of TLCP, the phase separation between TLCP and the matrix became serious.…”

Section: Introductionmentioning

confidence: 99%

“…This investigation indicated that the concentration of LLCP reinforcement was crucial for the preparation and performance of composites. 16 Another method to fabricate liquid crystalline polymeric composites was melt blending thermotropic liquid crystalline polymers (TLCPs) with a thermoplastic (e.g., PP, PA) or thermosetting matrix (e.g., epoxy resin). 17−20 With an increase in the amount of TLCP, the phase separation between TLCP and the matrix became serious.…”

Section: ■ Introductionmentioning

confidence: 99%

Self-Generation of a Nanofibrous Structure Enables Facile Preparation and Processing of a Liquid Crystalline Polymeric Composite with Intrinsic Flame Retardancy

Liu,

Wu,

Peng

et al. 2024

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Thermotropic liquid crystalline polymers (TLCPs) usually act as reinforcement to prepare composites; however, poor interfacial adhesion between two materials leads to restricted enhancement in performance. Although adding a flame retardant is an effective method to extend the application fields of composites, it results in serious phase separation. To address the above challenges, a new strategy to design high-performance in-situreinforced composites with intrinsic flame retardancy is presented in this work. A naphthalene monomer with a kinked structure reduces the regularity of molecular chains, which improves the processability and forms a relatively flexible polymer bulk. The rest of the domains are more rigid and peculiarly form nanofiber reinforcement. The resultant composites possess high glass transition temperature (T g > 200 °C), excellent processability (minimum complex melt viscosity ∼6.4 × 10 3 Pa•s), and great intrinsic flame retardancy. This would be an effective solution to reconcile the contradictory processability, phase separation, and flame retardancy of composites.

show abstract

“…Nanocomposites often possess a number of advantages over their related macrocomposites, including the use of smaller amounts of the nanoscale dispersion [9,10], and excellent high- [11] and slow-speed-resistance properties [12,13]. Ionic molecularly modified composites have been prepared by mixing salt-type rigid-rod molecules with a polymer matrix in a cosolvent; the mechanical properties of such composites increased upon increasing the degree of rigi-rod reinforcement [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Physical properties of epoxy resin self‐reinforced with organic rigid‐rod compounds

Lin

Han

Chen

et al. 2007

Polymer Engineering & Sci

View full text Add to dashboard Cite

In this study, nanoscale organic rigid-rod compounds were utilized as self-reinforcing composites to enhance the physical properties of an epoxy resin diglycidylether of bisphenol A (DGEBA). First, DGEBA was used to react with an aromatic diisocyanate of methylene diphenyl isocyanate (MDI) to form an urethane linkage. Next, four different organic rigid-rod compounds including 4 0 -hydroxyphenyl-4-hydroxybenzoate, phenyl 4-hydroxybenzoate, 4,4 0 -isopropylidenediphenol, and 2naphthol were incorporated to react individually with the remaining isocyanate groups of the MDI units after the previous step. Finally, the four different rigidrod-modified DGEBA systems were examined using nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, scanning electric microscopy, and mechanical property analyses. Each of the four rigid-rod-reinforced DGEBA systems exhibited greatly improved mechanical properties, e.g., higher tensile strengths and fracture energies. POLYM. ENG.

show abstract

Mechanical properties of molecular composites. I. Poly (p-phenylene terephthalamide) anion molecules dispersed in poly(4-vinylpyridine)

Cited by 19 publications

References 18 publications

Mast cells in Wallerian degeneration: Morphologic and ultrastructural changes

Mast cells in Wallerian degeneration: Morphologic and ultrastructural changes

Self-Generation of a Nanofibrous Structure Enables Facile Preparation and Processing of a Liquid Crystalline Polymeric Composite with Intrinsic Flame Retardancy

Physical properties of epoxy resin self‐reinforced with organic rigid‐rod compounds

Contact Info

Product

Resources

About