Thermal oxidative stabilization of polyacrylonitrile precursor fiber—progression of morphological structure and mechanical properties

Carbon ◽  
1992 ◽  
Vol 30 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Pinghua Wang ◽  
Jie Liu ◽  
Zhongren Yue ◽  
Rengyuan Li
Keyword(s):  
Mechanical Properties ◽  
Morphological Structure ◽  
Precursor Fiber ◽  
Oxidative Stabilization ◽  
Polyacrylonitrile Precursor

Mechanical properties of the tracheal mucosal membrane in the rabbit. II. Morphometric analysis

2000 ◽  
Vol 88 (3) ◽  
pp. 1022-1028 ◽  
Author(s):  
Lu Wang ◽  
Kenneth L. Pinder ◽  
Joel L. Bert ◽  
Mitsushi Okazawa ◽  
Peter D. Paré
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Mechanical Load ◽  
Morphological Structure ◽  
Longitudinal Direction ◽  
Smooth Muscle Contraction ◽  
Elastic Fibers ◽  
Tissue Samples ◽  
Mucosal Membrane ◽  
Simple Geometry

Folding of the airway mucosal membrane provides a mechanical load that impedes airway smooth muscle contraction. Mechanical testing of rabbit tracheal mucosal membrane showed that the membrane is stiffer in the longitudinal than in the circumferential direction of the airway. To explain this difference in the mechanical properties, we studied the morphological structure of the rabbit tracheal mucosal membrane in both longitudinal and circumferential directions. The collagen fibers were found to form a random meshwork, which would not account for differences in stiffness in the longitudinal and circumferential directions. The volume fraction of the elastic fibers was measured using a point-counting technique. The orientation of the elastic fibers in the tissue samples was measured using a new method based on simple geometry and probability. The results showed that the volume fraction of the elastic fibers in the rabbit tracheal mucosal membrane was ∼5% and that the elastic fibers were mainly oriented in the longitudinal direction. Age had no statistically significant effect on either the volume fraction or the orientation of the elastic fibers. Linear correlations were found between the steady-state stiffness and the quantity of the elastic fibers oriented in the direction of testing.

scholarly journals Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2863
Author(s):  
Hyunchul Ahn ◽  
Sang Young Yeo ◽  
Byoung-Sun Lee
Keyword(s):  
Carbon Fibers ◽  
Material Properties ◽  
Mechanical Performance ◽  
Superior Performance ◽  
Materials Processing ◽  
Effective Strategy ◽  
Precursor Fiber ◽  
Polyacrylonitrile Precursor

Although polyacrylonitrile (PAN)-based carbon fibers have been successfully commercialized owing to their excellent material properties, their actual mechanical performance is still much lower than the theoretical values. Meanwhile, there is a growing demand for the use of superior carbon fibers. As such, many studies have been conducted to improve the mechanical performance of carbon fibers. Among the various approaches, designing a strong precursor fiber with a well-developed microstructure and morphology can constitute the most effective strategy to achieve superior performance. In this review, the efforts used to modulate materials, processing, and additives to deliver strong precursor fibers were thoroughly investigated. Our work demonstrates that the design of materials and processes is a fruitful pathway for the enhancement of the mechanical performance of carbon fibers.

Production Parameters Optimization of Polyacrylonitrile Precursor Fiber

2014 ◽  
Vol 513-517 ◽  
pp. 100-103
Author(s):  
Yi Wang ◽  
Yong Sheng Ding ◽  
Kuang Rong Hao
Keyword(s):  
Carbon Fiber ◽  
Vital Role ◽  
Parameters Optimization ◽  
Optimization Approach ◽  
Precursor Fiber ◽  
Fiber Production ◽  
Production Parameters ◽  
Working Together ◽  
The Relationship ◽  
Polyacrylonitrile Precursor

Polyacrylonitrile precursor fiber as the as-spun fiber of carbon fiber plays a vital role in carbon fiber performances. In order to optimize the production process and the fiber performances of polyacrylonitrile precursor fiber, a production parameters optimization approach is proposed to find the relationship between the initial input and the final output of this fiber production and help to determine the production parameters according to the fiber performances required. Because fiber production is a complex industry process with a lot of parameters working together and them all have effect on the final performances, so this optimization is a multi-objective optimization which is based on particle swarm optimization formulas and production data. This approach can maintain the diversity of solutions, improve the accuracy of production parameters determining and provide a optimization of polyacrylonitrile precursor fiber.

Fabrication and Mechanical Properties of Double-Shell Thermal Energy Storage Microcapsules Applied as Environmental Temperature-Controlling Materials in Building

2010 ◽  
Vol 96 ◽  
pp. 81-86 ◽  
Author(s):  
Jun Feng Su ◽  
Sheng Bao Wang ◽  
Zhen Huang
Keyword(s):  
Mechanical Properties ◽  
Energy Storage ◽  
Shell Structure ◽  
Environmental Temperature ◽  
Morphological Structure ◽  
Average Diameter ◽  
Formaldehyde Resin ◽  
Plastic Behavior ◽  
Shell Analysis ◽  
Change Temperature

The aim of the present work was to fabricate heat energy storage microcapsules, which could be used in indoor-wall materials as environmental temperature-controller. Melamine formaldehyde resin (MF) double-shell structure microcapsules were fabricated and the mechanical properties of shell were investigated. The average diameter of microcapsules was in the range of 5-10 μm, and the globular surface was smooth and compact. The mechanical properties of shell were evaluated through observing the surface morphological structure change after pressure by means of scanning electron microscopy (SEM). The results showed that a yield point was found both on single and double shell, and when the press was beyond the point the microcapsules showed plastic behavior. In addition, the mechanical intensity of double-shell microcapsules was better than that of single shell. Analysis of DSC indicated that the phase change temperature was not affected by the double –shell structure.

Direct polymer additive tooling – effect of additive manufactured polymer tools on part material properties for injection moulding

2019 ◽  
Vol 25 (10) ◽  
pp. 1575-1584 ◽  
Author(s):  
Achim Kampker ◽  
Johannes Triebs ◽  
Sebastian Kawollek ◽  
Peter Ayvaz ◽  
Tom Beyer
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Mechanical Behaviour ◽  
Material Properties ◽  
Tensile Elongation ◽  
Morphological Structure ◽  
Mould Insert ◽  
Content Type ◽  
3D Print ◽  
Standard Specimens

Purpose This study aims to investigate the influence of additive manufactured polymer injection moulds on the mechanical properties of moulded parts. Therefore, polymer moulds are used to inject standard specimens to compare material properties to specimens produced using a conventional aluminium tool. Design/methodology/approach PolyJet technology is used to three-dimensional (3D)-print a mould insert in Digital ABS and selective laser sintering (SLS) technology is used to 3D-print a mould insert in polyamide (PA) 3200 GF. A conventionally aluminium milled tool serves as reference. Standard specimens are produced to compare resulting mechanical properties, shrinkage behaviour and morphology. Findings The determined material characteristics of the manufactured prototypes from the additive manufactured tools show differences in terms of mechanical behaviour to those from the aluminium reference tool. The most significant differences are an up to 25 per cent lower tensile elongation and an up to 63 per cent lower elongation at break resulting in an embrittlement of the specimens produced. These differences seem to be mainly due to the different morphological structure caused by the lower thermal conductivity and greater surface roughness of the polymer tools. Research limitations/implications The determined differences in mechanical behaviour can partly be assigned to differences in surface roughness and morphological structure of the resulting parts. The exact extend of either cause, however, cannot be clearly determined. Originality/value This study provides a comparison between the part material properties from conventionally milled aluminium tools and polymer inserts manufactured via additive tooling.

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