Analysis and Research of PPTA Erosion of the Ultrasonication

2011 ◽  
Vol 239-242 ◽  
pp. 314-317
Author(s):  
Zheng Feng Zhu ◽  
Da Peng Qi ◽  
Jun Hua Wang ◽  
Qian Han ◽  
Li Li Cai
Keyword(s):  
Mechanical Property ◽  
Infrared Spectrum ◽  
Kinetic Theory ◽  
Breaking Strength ◽  
Weak Link ◽  
Degree Of Polymerization ◽  
Distilled Water ◽  
Elongation At Break ◽  
Molecular Kinetic Theory

PPTA fibers made by China ShenMa Group Co., Ltd and Kevlar49 fibers made by Dupont as experimental materials were used in this paper. The differences of molecule structures were contrasted through infrared spectrum and degree of polymerization-counting by the detections of viscosity. The PPTA fibers were put into distilled water and seawater made by ourselves respectively, then ultrasonication were used to deal with them. After this, using the SEM to observe, found that the cracks appear on the fibers surfaces, presented the fibrillation and plush-like microfine fibers. Meanwhile the strength weak-link increased and breaking strength and elongation at break of fibers lowered after ultrasonication. Molecular kinetic theory was used in this paper to study loss of fibers the mechanical property.

Preparation and properties of polyurethane coatings modified by polysilazane

2019 ◽  
Vol 32 (6) ◽  
pp. 611-619 ◽  
Author(s):  
Xiaoli Liu ◽  
Zhen Ge ◽  
Wenguo Zhang ◽  
Yunjun Luo
Keyword(s):  
Mechanical Property ◽  
Photoelectron Spectroscopy ◽  
Composite Coatings ◽  
Composite Films ◽  
Dip Coating ◽  
Water Contact ◽  
Research Attention ◽  
Elongation At Break ◽  
Coating Method ◽  
Dip Coating Method

Due to their unique physicochemical properties, polysilazanes exhibit excellent performance when combined with some resin matrixes, which had drawn great research attention. In this article, polyurethane (PU) was firstly prepared by polytetrahydrofuran glycol, isophorone diisocyanate, and 1,4-butanediol as main materials. Then, the prepared PU was blended with polysilazane by mixing the two solutions together, which was cured to films via dip-coating method at room temperature. The structure, thermal stability, and surface properties of the composite coatings were investigated by Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results demonstrated that after modification with polysilazane, the heat resistance, hydrophobicity, and mechanical property of the PU coatings were improved. When the content of polysilazane was 6 wt%, the mechanical property of the composite films was optimized, with a maximum tensile strength of 25.7 MPa and elongation at break of 797%. Meanwhile, the water contact angle of the composite film was 107° and the water absorption reached a minimum of 2.1%, which showed improved hydrophobicity and water resistance.

The Historical Background: Molecular Theory as of 1900

2020 ◽  
pp. 33-87
Author(s):  
George E. Smith ◽  
Raghav Seth
Keyword(s):  
Physical Chemistry ◽  
Nineteenth Century ◽  
Kinetic Theory ◽  
Historical Context ◽  
Molecular Theory ◽  
Historical Background ◽  
Kinetic Theory Of Gases ◽  
Comprehensive Review ◽  
Molecular Kinetic Theory ◽  
Wilhelm Ostwald

The task of this chapter is to explain the sense in which molecular theory—both molecular-kinetic theory and chemical-molecular theory—were still viewed as hypotheses as of 1900 and why the evidence bearing on them during the second half of the nineteenth century was insufficient for them to have achieved standing beyond this. The chapter reviews the strengths and limitations of the evidence in question, taking advantage of two widely read textbooks in physical chemistry published in the 1890s by Wilhelm Ostwald and Walther Nernst and a uniquely comprehensive review of the evidence pertaining to the kinetic theory of gases, by O. E. Meyer, published in 1899. This background defines the historical context within physics and chemistry for the developments covered in the remainder of the monograph.

scholarly journals Sago Starch-Mixed Low-Density Polyethylene Biodegradable Polymer: Synthesis and Characterization

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Md Enamul Hoque ◽  
Tan Jie Ye ◽  
Leng Chuan Yong ◽  
KhairulZaman Mohd Dahlan
Keyword(s):  
Mechanical Property ◽  
Young’S Modulus ◽  
Biodegradable Polymer ◽  
Young's Modulus ◽  
Starch Content ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
Content Increase ◽  
Sago Starch ◽  
Elongation At Break

This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable polymer. Firstly, the effect of variation of starch content on mechanical property (elongation at break and Young’s modulus) and biodegradability of the polymer was studied. The LDPE was combined with 10%, 30%, 50%, and 70% of sago for this study. Then how the cross-linking with trimethylolpropane triacrylate (TMPTA) and electron beam (EB) irradiation influence the mechanical and thermal properties of the polymer was investigated. In the 2nd study, to avoid overwhelming of data LDPE polymer was incorporated with only 50% of starch. The starch content had direct influence on mechanical property and biodegradability of the polymer. The elongation at break decreased with increase of starch content, while Young’s modulus and mass loss (i.e., degradation) were found to increase with increase of starch content. Increase of cross-linker (TMPTA) and EB doses also resulted in increased Young’s modulus of the polymer. However, both cross-linking and EB irradiation processes rendered lowering of polymer’s melting temperature. In conclusion, starch content and modification processes play significant roles in controlling mechanical, thermal, and degradation properties of the starch-mixed LDPE synthetic polymer, thus providing the opportunity to modulate the polymer properties for tailored applications.

Research on Structure and Mechanical Properties of Epoxy Resin/Clay Nanocomposites by Shock Wave Method

2012 ◽  
Vol 501 ◽  
pp. 366-371 ◽  
Author(s):  
Guang Yi Lin ◽  
Xue Chen Mu ◽  
Dian Wei Qu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Shock Wave ◽  
Epoxy Resin ◽  
Process Condition ◽  
Interlayer Spacing ◽  
Clay Nanocomposites ◽  
Wave Method ◽  
Optimal Process ◽  
Elongation At Break

Epoxy resin / clay nanocomposites prepared by shock wave method. The structure and mechanical properties including hardness, stress, strain and elongation at break were investigated. XRD was used to observe the interlayer spacing of the OMMT and SEM was used to survey the morphology of nanocomposites system. The results indicated that nano-montmorillonite can effectively increase the mechanical property of the material. The nano-montmorillonite was well dispersed in the epoxy matrix. The optimal process condition is that shock time 5min, nano-MMT content of 5%, duty cycle 1:3, shock depth 3cm.

Modification of Polyurethane by Tung Oil Anhydride-Ester Polyol

2012 ◽  
Vol 554-556 ◽  
pp. 191-194 ◽  
Author(s):  
Han Zhou Sun ◽  
Xun Jun Du ◽  
Jin Hua Zhou ◽  
Lian Wu Xie ◽  
Yu Xiong Wu ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Heat Resistance ◽  
Hard Segment ◽  
Soft Segment ◽  
Morphological Structure ◽  
Elongation At Break ◽  
Tung Oil ◽  
Synthetic Resins ◽  
The World

Polyurethane (PU), one of the six main categories of synthetic resins, has been used extensively in industry all over the world. Tung oil anhydride-ester polyol (TOAEP), prepared from the China special vegetable oil, Tung oil, was introduced into PU structure. The mechanical property, heat-resistance and morphological structure of the modified PU were studied. Experimental results showed that the hardness and tensile strength of the modified PU increases as the dose of TOAEP increasing while the elongation at break decreases, and the heat-resistance has been improved after modification. The modified PU’s hard segment phase is compatible with the soft segment phase.

The molecular-kinetic theory of wetting

Langmuir ◽  
1994 ◽  
Vol 10 (1) ◽  
pp. 340-342 ◽  
Author(s):  
Robert A. Hayes ◽  
John Ralston
Keyword(s):  
Kinetic Theory ◽  
Molecular Kinetic Theory

Biomimetic Hemocompatible Nanofibrous Scaffolds as Potential Small-Diameter Blood Vessels by Bilayering Electrospun Technique

2011 ◽  
Vol 306-307 ◽  
pp. 1627-1630 ◽  
Author(s):  
He Yun Wang ◽  
Ya Kai Feng ◽  
Hai Yang Zhao ◽  
Ruo Fang Xiao ◽  
Jin Tang Guo
Keyword(s):  
Mechanical Properties ◽  
Blood Vessel ◽  
Breaking Strength ◽  
Small Diameter ◽  
Matrix Structure ◽  
Complex Matrix ◽  
Elongation At Break ◽  
Artificial Blood ◽  
Nanofibrous Scaffolds ◽  
Morphology And Mechanical Properties

In this paper, we prepared a scaffold composed of a polyurethane (PU) fibrous outside-layer and a gelatin-heparin fibrous inner-layer with mimicking morphology and mechanical properties of a native blood vessel by sequential bilayering electrospinning technology on a rotating mandrel-type collector. The scaffolds achieved the appropriate breaking strength (3.7 ± 0.13 MPa) and elongation at break (110 ± 8%). When the scaffolds were immersed in water for 1 h, the breaking strength decreased slightly to 2.2 ± 0.3 MPa, but the elongation at break increased up to 145 ± 21%. Heparin was released from the scaffolds at substantially uniform rate until the 9th day. The scaffolds were expected to mimic the complex matrix structure of native arteries, and had good hemocompatibility as an artificial blood vessel owing to the heparin release.

Effects of electron beam irradiation on structure and properties of ultra-high molecular weight polyethylene fiber

2017 ◽  
Vol 47 (6) ◽  
pp. 1357-1377 ◽  
Author(s):  
Dongliang Dai ◽  
Meiwu Shi
Keyword(s):  
Molecular Weight ◽  
Electron Beam ◽  
High Molecular Weight ◽  
Electron Beam Irradiation ◽  
Breaking Strength ◽  
Beam Irradiation ◽  
Elongation At Break ◽  
Gel Content ◽  
Ultra High Molecular Weight ◽  
Polyethylene Fibers

This study introduced trimethylolpropane trimethacrylate into ultra-high molecular weight polyethylene fibers through supercritical CO2 pretreatment before the fibers were irradiated under an electron beam. Significant differences, emerging in the ultra-high molecular weight polyethylene fibers’ gel content, mechanical properties, and creep property according to their different irradiation doses, were studied through one-way analysis of variance. Regression equations were established between the irradiation dose and the gel content, breaking strength, elongation at break, and creep rate by regression analysis. A reasonable irradiation dosage range was determined after a verification experiment and the impact trends were analyzed; additionally, the sensitized irradiation crosslinking mechanism of ultra-high molecular weight polyethylene fibers was preliminarily examined. Then the surface morphology, chemical structures, thermal properties, and crystal properties of treated ultra-high molecular weight polyethylene fibers were measured. The results showed that as the irradiation dose increased, the gel content first rose and then declined; the breaking strength decreased continuously; the elongation at break increased at first and then decreased; and the creep rate originally fell and then rose before finally declining slowly. Electron beam irradiation had a significant etching effect on the fibers’ surface, and both the melting point and crystallinity decreased slightly.

Sign in / Sign up

Export Citation Format

Share Document