Tensile properties dynamic

Eoams were extruded from low density polyethylene (LDPE) and blends of LDPE with syndiotactic polypropylene (sPP), using isobutane as the blowing agent. The extruded materials were characterised by measurement of dimensional stability at room temperature, density, tensile properties, dynamic stiffness, and crystallinity determined by differential scanning calorimetry. The sPP, with a slow crystallisation rate, did not interfere with the expansion of the LDPE, and enhanced the temperature resistance by in-situ crystallisation. The blends were flexible, dimensionally... 

Details are given of the physicochemical properties and in vitro resistance to encrustation of films of polycaprolactone or blends of polycaprolactone with a polyvinylpyrrolidone-iodine mixture. Films were characterised in terms of tensile properties, dynamic mechanical thermal analysis, dynamic contact angle, and SEM. 29 refs. 

A basic screen was used to evaluate the XP-2 at 35 PHR in the formulation listed in Table 1. The tests were tensile properties, dynamic and static heat stability, compatibility and surface energies... 

In general, however, the vulcanizates suffer from poor low temperature crystallization performance compared to a conventional sulfur cure, and also have inferior tensile and tear properties. Urethane cross-linking systems (37), eg, Novor 950 (see Table 3) are also extremely heat resistant, but exhibit inferior tensile and dynamic properties compared to conventional sulfur-cured vulcanizates. One added virtue is that they can be used in conjunction with sulfur systems to produce an exceUent compromise according to the ratios used (38). 

Finer dispersion of silica improves the mechanical and dynamic mechanical properties of the resultant composites. Figure 3.11a and b compares the tensile properties of the acrylic copolymer and terpolymers in the uncross-hnked and cross-linked states, respectively. 

Jha A. and Bhowmick A.K., Thermoplastic elastomeric blends of poly(ethyleneterephthalate) and carylate rubber 1. Influence of interaction on thermal, dynamic mechanical and tensile properties. Polymer, 38, 4337, 1997. 

Dynamic properties are more relevant than the more usual quasi-static stress-strain tests for any application where the dynamic response is important. For example, the dynamic modulus at low strain may not undergo the same proportionate change as the quasi-static tensile modulus. Dynamic properties are not measured as frequently as they should be simply because of high apparatus costs. However, the introduction of dynamic thermomechanical analysis (DMTA) has greatly widened the availability of dynamic property measurement. 

The main experimental methodology used is to directly characterize the tensile properties of CNTs/polymer composites by conventional pull tests (e.g. with Instron tensile testers). Similarly, dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA) were also applied to investigate the tensile strength and tensile modulus. With these tensile tests, the ultimate tensile strength, tensile modulus and elongation to break of composites can be determined from the tensile strain-stress curve. 

The presence of carboxylic groups, introduced by maleic anhydride, allows modified HTI to cross-link with unconventional agents, e. g. polyvalent metal oxides, hydroxides, polyamines. For instance, a sample of HTI, completely reacted with maleic anhydride, has been cured with ZnO at 153 °C for 20 minutes and o %d interestii tensile properties. Furthermore, the dynamic-mechanical spectra (Fig. 29)... 

Mechanical Properties. Dynamic mechanical properties were determined both in torsion and tension. For torsional modulus measurements, a rectangular sample with dimensions of 45 by 12.5 mm was cut from the extruded sheet. Then the sample was mounted on the Rheometrics Mechanical Spectrometer (RMS 800) using the solid fixtures. The frequency of oscillation was 10 rad/sec and the strain was 0.1% for most samples. The auto tension mode was used to keep a small amount of tension on the sample during heating. In the temperature sweep experiments the temperature was raised at a rate of 5°C to 8°C per minute until the modulus of a given sample dropped remarkably. The elastic component of the torsional modulus, G, of the samples was measured as a function of temperature. For the dynamic tensile modulus measurements a Rheometrics Solid Analyzer (RSA II) was used. The frequency used was 10 Hz and the strain was 0.5 % for all tests. 

Tensile properties were measured by using Shimadzu mechanical tester DSS5000. The cross head speed was 2 mm/min. Viscoelastic properties(tensile storage modulus and tan S) were measured by a tensile type dynamic mechanical analysis(SEIKO Instrument DMS 200). The... 

The miscibility of olefin copolymers such as ethylene-a-olefin copolymers was found to be controlled by the structural composition and the primary strucmre of the copolymers. Using these copolymers, binary blends with various compatibilities were prepared and the effects of compatibihty on mechanical properties in the binary blends were investigated. The tensile properties in binary blends of iPP with rubbery olefin copolymers are considerably influenced by the miscibility between iPP and the copolymers. The miscibility of iPP with other polyolefins is described in detail based on the dynamic mechanical properties, morphology observation, and solidification process. It is found that EBR, EHR, and EOR having more than 50 mol% of a-olefin are miscible with iPP in the molten state. In the solid state, the miscible copolymers are dissolved in the amorphous region of iPP, although the copolymers are excluded from crystalhne lattice of iPP. The isotactic propylene sequence in the EP copolymers with a propylene-unit content of more than 84 mol% participates in the crystallization process of iPP, resulting that a part of the EP copolymers is included in the crystalline lattice of iPP. 

Bikiaris, D. N. and Karayannidis, G. P., Dynamic thermomechanical and tensile properties of chain-extended PET, J. Appl. Polym. ScL, 70, 797 (1998). 

The resulting cross-linked network can be characterized by studying the chemical and physical property changes that have occurred in the elastomers. The physical properties of vulcan-Izates that are usually evaluated are (a) modulus, (b) ultimate tensile properties, (c) swelling ratio, (d) glass-transition temperature (Tg), (e) dynamic mechanical properties and (f) creep... 

B. Bhushan, T. J. Ma, and T. Higashioji. Tensile and dynamic mechanical properties of improved ultrathin polymeric films. J. AppL Polym. ScL, 83... 

Tensile Properties Similar to polyethylene, the stress-strain curve of JSR RB has a yield point. Above the yield point, the stress-strain curve continues to increase with elongation, then breaks. This kind of stress-strain curve is similar to EVA and indicates a characteristic property lying somewhere between amorphous and crystalline polymers. The dynamic properties of JSR RB can be improved by stretch-... 

Yarns are available in a variety of deniers and merge types that vary in the balance of tensile properties. Special finishes can be applied to increase lubricity, improve fatigue in wet applications, or provide better UV resistance. Ropes using Kevlar or Twaron are particularly useful for static applications or where maximum modulus is required. Technora-based ropes are suited for dynamic applications where resistance to fatigue is important. 

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