High-performance all-aromatic liquid crystalline esteramide-based thermosets

2018 ◽  
Vol 31 (6) ◽  
pp. 631-639 ◽  
Author(s):  
Yiheng Dai ◽  
Xiangyu Bi ◽  
Theo J Dingemans ◽  
Qingbao Guan
Keyword(s):  
Tensile Strength ◽  
Terephthalic Acid ◽  
High Performance ◽  
Liquid Crystalline ◽  
High Concentration ◽  
Elongation At Break ◽  
New Family ◽  
Hydrogen Bonding Interactions ◽  
Naphthoic Acid ◽  
Melt Condensation

We have synthesized and characterized a new family of nematic all-aromatic polyesteramide thermosets based on 6-hydroxy-2-naphthoic acid (HNA), terephthalic acid (TA), and 4-acetamidophenol (AAP). In order to incorporate a high concentration of the amide-based monomer (AAP), the melt transition ( T K-N) and melt viscosity had to be lowered in order to maintain melt processable intermediates. Precursor thermoplastic reactive oligomers, end-capped with phenylethynyl functionalities, were prepared using standard melt condensation techniques with a target M n of 1000–9000 g mol−1. The reactive oligomers with 20–30 mol% AAP could easily be processed into films, and the films exhibit good tensile properties in terms of tensile strength (70–80 MPa) and elongation at break (7–10%). A glass transition of 191°C could be obtained when a 1000 g mol−1 oligomer (HNA/TA/AAP(20)–1 K) was thermally cross-linked. When the AAP concentration reaches 35 mol%, the rigidity of the backbone and the hydrogen bonding interactions are enhanced, which make HNA/TA/AAP(35) polymers difficult to process.

Morphology of High-Performance Rigid-Rod Polymer Fibers and Molecular Composites

1989 ◽  
Vol 47 ◽  
pp. 338-339
Author(s):  
W.W. Adams ◽  
S. J. Krause
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Liquid Crystalline ◽  
Molecular Level ◽  
Synergistic Effects ◽  
Tensile Modulus ◽  
Commercial Development ◽  
The Matrix ◽  
Molecular Composites ◽  
Rigid Rod

Rigid-rod polymers such as PBO, poly(paraphenylene benzobisoxazole), Figure 1a, are now in commercial development for use as high-performance fibers and for reinforcement at the molecular level in molecular composites. Spinning of liquid crystalline polyphosphoric acid solutions of PBO, followed by washing, drying, and tension heat treatment produces fibers which have the following properties: density of 1.59 g/cm3; tensile strength of 820 kpsi; tensile modulus of 52 Mpsi; compressive strength of 50 kpsi; they are electrically insulating; they do not absorb moisture; and they are insensitive to radiation, including ultraviolet. Since the chain modulus of PBO is estimated to be 730 GPa, the high stiffness also affords the opportunity to reinforce a flexible coil polymer at the molecular level, in analogy to a chopped fiber reinforced composite. The objectives of the molecular composite concept are to eliminate the thermal expansion coefficient mismatch between the fiber and the matrix, as occurs in conventional composites, to eliminate the interface between the fiber and the matrix, and, hopefully, to obtain synergistic effects from the exceptional stiffness of the rigid-rod molecule. These expectations have been confirmed in the case of blending rigid-rod PBZT, poly(paraphenylene benzobisthiazole), Figure 1b, with stiff-chain ABPBI, poly 2,5(6) benzimidazole, Fig. 1c A film with 30% PBZT/70% ABPBI had tensile strength 190 kpsi and tensile modulus of 13 Mpsi when solution spun from a 3% methane sulfonic acid solution into a film. The modulus, as predicted by rule of mixtures, for a film with this composition and with planar isotropic orientation, should be 16 Mpsi. The experimental value is 80% of the theoretical value indicating that the concept of a molecular composite is valid.

Properties of Random PSF/PES Copolymers as High-Performance Polymers

2011 ◽  
Vol 217-218 ◽  
pp. 1606-1610
Author(s):  
Dong Jiang ◽  
Xiao Ran Zhang ◽  
Yan Mei Ma ◽  
Cheng You Ma
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Glass Transition ◽  
High Performance ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Elongation At Break ◽  
Glass Transition Temperatures ◽  
High Performance Polymers ◽  
Diphenyl Sulfone

A series of random polysulfone/polyethersulfone (PSF/PES) copolymers were synthesized by the polycondensation of 4, 4'-isopropylidendiphenol, 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone in the presence of K2CO3. We obtained a series of copolymers by changing the molar ratio of 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-isopropylidendiphenol (it was marked as the ratio of S:A). The copolymers have the similar solubility with polyethersulfone. They also have high glass transition temperatures (Tg: 199°C~229°C) and 5% weight loss temperatures (4, 4'-isopropylidendiphenol: 4, 4΄-dihyolroxy diphenyl sulfone=1:1, Td5=497°C). At the same time the elongation at break is much higher than that of PES, while the tensile strength is a little lower than that of PES.

Synthesis and properties of random polysulfone/polyethersulfone copolymers as high-performance polymers

2011 ◽  
Vol 31 (4) ◽  
Author(s):  
Yi-Nan Zhang ◽  
Shu-Ling Zhang ◽  
Yan-Hua Yang ◽  
Hong-Yi Qin ◽  
Dong Jiang
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
High Performance ◽  
Excellent Thermal Stability ◽  
Elongation At Break ◽  
High Performance Polymers

Abstract A series of random polysulfone/polyethersulfone (PSF/PES) copolymers were synthesized by the polycondensation of 4,4′-isopropylidenediphenol, 4,4′-dihydroxyldiphenylsulfone, and 4,4′-dichlorodiphenylsulfone in the presence of potassium carbonate. The resulting copolymers displayed similar solubility with PSF and PES. The glass transition temperature and the 5% weight loss temperature of these copolymers varied in the range of 199°C–299°C and 467°C–498°C, respectively, which showed excellent thermal stability. Moreover, the elongation at break of these copolymers was much higher than that of PES, whereas the tensile strength was a little lower.

Synthesis and Characterization of Biodegradable Aliphatic-Aromatic Copolyesters Nanocomposites Containing POSS

2011 ◽  
Vol 236-238 ◽  
pp. 2028-2031
Author(s):  
Bing Tao Wang ◽  
Yan Zhang ◽  
Zheng Ping Fang
Keyword(s):  
Tensile Strength ◽  
Terephthalic Acid ◽  
Interfacial Adhesion ◽  
Synthesis And Characterization ◽  
Mechanical And Thermal Properties ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Elongation At Break ◽  
The Matrix

Biodegradable aliphatic-aromatic copolyesters/POSS nanocomposites were synthesized via in situ melt copolycondensation of terephthalic acid (TPA), poly(L-lactic acid) oligomer (OLLA), 1,4-butanediol (BDO) and polyhedral oligomeric silsesquioxanes (POSS) reagents (POSS-NH2 and POSS-PEG). The morphologies and dispersions of two POSS reagents in the nanocomposites and their effects on the mechanical and thermal properties were investigated. TEM and XRD characterizations confirmed that POSS-NH2 formed crystalline microaggregates and took poor dispersions in the nanocomposite, while POSS-PEG had better dispersion in the matrix. Due to the good dispersion and interfacial adhesion of POSS-PEG with the copolyester PBTL matrix, the tensile strength and the Young’s modulus greatly increased for PBTL/POSS-PEG nanocomposite. Moreover, compared with POSS-NH2 the existence of POSS-PEG imparted PBTL good flexibility and increased the mobility of the chains, so the glass-transition temperature and the heat of melting as well as the elongation at break were obviously influenced for PBTL/POSS-PEG nanocomposite.

Harnessing of non-fibrous textile for production of high performance easy-care cotton fabrics

2019 ◽  
Vol 48 (2) ◽  
pp. 156-168 ◽  
Author(s):  
Kh.M. Mostafa ◽  
Heba Ameen ◽  
Mahmoud Morsy ◽  
Amal El-Ebissy ◽  
Mohamed Adel ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Electron Microscope ◽  
Cotton Fabric ◽  
High Performance ◽  
Strength Properties ◽  
Cotton Fabrics ◽  
Cross Linking ◽  
Great Loss ◽  
Elongation At Break ◽  
Content Type

Purpose This study aims to explore the incorporation of starch nanoparticles (SNPs) in cross-linking formulation of cotton fabrics to see their impact on fabric performance like tensile strength, dry wrinkle recovery angles, elongation at break, degree of whiteness and increase in weight as well as durability. Design/methodology/approach SNPs of size around 80-100 nm were successfully prepared from native maize starch by Nano precipitation technique and confirmed instrumentally by scanning electron microscope (SEM), transmittance electron microscope (TEM), Fourier transformer infrared (FTIR) spectroscopy and particle size analyzer. The latter were incorporated in cross-linking formulation of cotton fabrics encompassing different concentrations of citric acid and sodium hypophosphite at different curing time and temperature in 100 ml distilled water to a wet pickup of ca. 85 per cent. The fabric samples were dried for 3 min at 85°C and cured at specified temperatures for a specified time intervals in thermo fixing oven according to pad-dry-cure method. Findings FTIR spectra and SEM micrograph signified the chemical structure and surface morphology of cotton fabric before and after finishing in absence and presence of SNPs. Cotton fabric samples finished in presence of SNPs showed a higher tensile strength, elongation at break, comparable dry wrinkle recovery angles and degree of whiteness than that finished in their absence. On the other hand, the enhancement in the aforementioned performance reflects the positive impact of incorporation of SNPs in textile finishing especially with strength properties; which are one of the important requirements for industrial fabrics that can be used widely in heavy-duty applications. Research limitations/implications SNPs with its booming effect with respect to biodegradability, reactivity and higher surface area can be used as a novel reinforcement permanent finish for cotton fabrics instead of more hazardous materials likes poly acrylate and monomeric compounds. Practical implications As SNPs biopolymers is one of the important reinforcement agents, so it was expected that it would minimize the great loss in strength properties during easy-care cotton finishing and improve the fabric performance. Originality/value The novelty addressed here is undertaken with a view to remediate some of the serious defects of easy-care cotton fabrics using poly carboxylic acids; especially with the great loss in strength properties by virtue of using SNPs as a permanent finish. Besides, to the authors’ knowledge, there is no published work so far concerning the use of SNPs as an innovative base for production of easy-care finished cotton textiles with high performance.

Hybrid siliconized–epoxidized EPDM/polyurethane (eEPDM-g-APTES/HTPDMS/PU) matrices for potential application in cable insulation

2019 ◽  
Vol 28 (8-9) ◽  
pp. 589-597
Author(s):  
Manokaran Vadivel ◽  
Moses Suresh Chandra Kumar ◽  
Jabbar Abbas Mohaideen ◽  
Muthukaruppan Alagar ◽  
Murugesan Sankarganesh ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
High Performance ◽  
Young's Modulus ◽  
Morphological Properties ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Elongation At Break ◽  
Morphological Studies ◽  
Percentage Concentration

Hybrid matrices (epoxidized of ethylene–propylene–diene monomer (eEPDM) -g-aminopropyltriethoxysilane (APTES)/hydroxyl terminated polydimethylsiloxane (HTPDMS)/polyurethane (PU)) were developed based on eEPDM with 3-APTES coupling agent and varying weight percentages (0.75, 1.50, 2.25, and 3.00 wt%) of PU prepolymer as coreactant using 7.5 wt% of HTPDMS as chain extender using suitable experimental conditions. The formation of hybrid matrices and their structure were characterized by Fourier transform infrared (FTIR). The thermal and morphological properties of the hybrid matrices were analyzed using differential scanning calorimetry and scanning electron microscope, respectively. Mechanical properties (tensile strength, elongation at break (%), Young’s modulus, and hardness) were characterized as per ASTM standards. Data resulted from mechanical studies, it was noticed that the incorporation of 3-APTES, HTPDMS, and PU into eEPDM has improved the elongation at break (%) and lowered the values of tensile strength, Young’s modulus, and hardness according to the percentage concentration. Morphological studies indicate the presence of heterogeneous morphology. Data obtained from different studies, it suggested that the hybrid matrices developed in the present work can be used as cable insulates for high-performance industrial and engineering applications.

scholarly journals Carbon Fiber Composite Molecular Sieves for Gas Separation

1994 ◽  
Vol 344 ◽  
Author(s):  
M. Jagtoyen ◽  
F. Derbyshire ◽  
N. Brubaker ◽  
Y. Q. Fel ◽  
G. Kimber ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Carbon Fibers ◽  
Molecular Sieves ◽  
High Performance ◽  
Fiber Composite ◽  
High Strength ◽  
Mesophase Pitch ◽  
High Concentration ◽  
Carbon Fiber Composite ◽  
Temperature Oxidation

IntroductionCarbon fibers are produced commercially from rayon, phenolics, polyacrylonitrile (PAN), or pitch. The last are further divided into fibers produced from isotropic pitch precursors, and those derived from pitch that has been pretreated to introduce a high concentration of carbonaceous mesophase. Over the past few decades, interest in research and manufacturing carbon fibers has overwhelmingly centered on producing fibers with high tensile strength and high modulus for lightweight, high performance composites, where polymers, metals, and carbon can form the continuous matrix. The fibers most commonly used in advanced materials are produced from PAN or mesophase pitch. Graphitized mesophase pitch fibers tend to have higher modulus and lower tensile strength than the PAN-based equivalents. They have advantages in applications requiring high stiffness, high electrical and thermal conductivity, low thermal expansion, and high temperature oxidation resistance, while PAN fibers are employed where high strength is required.

Blending of Polyvulcanize Natural Rubber

2014 ◽  
Vol 879 ◽  
pp. 224-229
Author(s):  
Wan Mohd Faruq Wan Mohd Ridzwan ◽  
Dzaraini Kamarun ◽  
Azemi Samsuri ◽  
Ahmad Faiza Mohd ◽  
Che Mohd Som Said
Keyword(s):  
Thin Film ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Butyl Acrylate ◽  
High Performance ◽  
Natural Rubber Latex ◽  
Butyl Methacrylate ◽  
Rubber Latex ◽  
Elongation At Break ◽  
Acrylate Copolymer

Natural rubber (NR) latex is widely used in the manufacture of thin film barrier products such as gloves and condom. However, due to its low Tg, film casted from NR latex is soft and tacky, and needed to be strengthened to produced high performance products. Films of prevulcanized natural rubber latex (PVNR) blended with nanosized copolymer of n-butyl acrylate/butyl methacrylate (BA/BMA) were prepared at three different ratios of acrylate copolymer: PVNR. The tensile strength and elongation at break of films prepared decreased with increasing ratios of acrylate copolymer:PVNR. FESEM images showed the occurrence of agglomeration of the acrylate copolymers with PVNR molecules. The degree of agglomeration of the blended molecules increased with percentages of copolymer added. The decrease in the tensile strength and elongation at break may due to the agglomeration of the blended molecules suggesting poor dispersion and/or destabilization of PVNR molecules.

Preparation and Properties Research of PA6/PLA Blends Toughening Modified by TPU

2012 ◽  
Vol 200 ◽  
pp. 278-281 ◽  
Author(s):  
Yi Chen ◽  
Wei Jian Xu ◽  
Guang Sheng Zeng ◽  
Xiao Hong Zeng ◽  
Wen Yong Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Fracture Behavior ◽  
Thermoplastic Polyurethane ◽  
Polyamide 6 ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Thermal And Mechanical Properties ◽  
Elongation At Break ◽  
The Impact

Polyamide 6/Poly(lactic acid) (PA6/PLA) blends introduce the degradability of PLA to high performance PA6, but the bad toughness of both PA6 and PLA limits the application of blends. Aiming at this deficiency, thermoplastic polyurethane (TPU) was used as an additive for modifying the toughness of PA6/PLA blends. PA6/PLA/TPU blends at various compositions were prepared by melt blending, the effects of blend compositions on the morphology, thermal and mechanical properties of blends were investigated. The results showed that the addition of TPU improves the compatibilization between PA6 and PLA and makes the blends show more obvious plastic fracture behavior than PA6/PLA.When the content of PLA in PA6/PLA increases, the impact and tensile strength of blends decrease slightly with the intense decrease of the elongation at break, adding TPU into PA6/PLA blends strengthens the toughness of blends, but the tensile strength of blends decreases. Moreover, the crystallinity of PA6 /PLA blend is hampered by TPU.

Co-planar two-dimensional Metal-Insulator-Semiconductor Capacitor: Numerical study of the device electrostatics.

2017 ◽  
Author(s):  
Varun Bheemireddy
Keyword(s):  
Space Charge ◽  
High Performance ◽  
Numerical Study ◽  
2D Materials ◽  
Space Charge Density ◽  
Two Dimensional ◽  
Short Channel ◽  
Metal Insulator ◽  
Metal Insulator Semiconductor ◽  
New Family

The two-dimensional(2D) materials are highly promising candidates to realise elegant and e cient transistor. In the present letter, we conjecture a novel co-planar metal-insulator-semiconductor(MIS) device(capacitor) completely based on lateral 2D materials architecture and perform numerical study of the capacitor with a particular emphasis on its di erences with the conventional 3D MIS electrostatics. The space-charge density features a long charge-tail extending into the bulk of the semiconductor as opposed to the rapid decay in 3D capacitor. Equivalently, total space-charge and semiconductor capacitance densities are atleast an order of magnitude more in 2D semiconductor. In contrast to the bulk capacitor, expansion of maximum depletion width in 2D semiconductor is observed with increasing doping concentration due to lower electrostatic screening. The heuristic approach of performance analysis(2D vs 3D) for digital-logic transistor suggest higher ON-OFF current ratio in the long-channel limit even without third dimension and considerable room to maximise the performance of short-channel transistor. The present results could potentially trigger the exploration of new family of co-planar at transistors that could play a signi significant role in the future low-power and/or high performance electronics.<br>

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