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Mechanical Properties of Polymers and Composites
14 Dec 1993-
TL;DR: In this article, the authors discuss various mechanical properties of fiber-filled composites, such as elastic moduli, creep and stress relaxation, and other mechanical properties such as stress-strain behavior and strength.
Abstract: Mechanical Tests and Polymer Transitions * Elastic Moduli * Creep and Stress Relaxation * Dynamical Mechanical Properties * Stress-Strain Behaviour and Strength * Other mechanical Properties * Particulate-Filled Polymers * Fiber- Filled Composites and Other Composites.
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TL;DR: In this article, the properties of poly(e-caprolactone) and benzoxazine resins are studied by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA).
125 citations
TL;DR: In this paper, the effect of maleated polyethylene (PE-g-MA) modifiers on the impact strength and moduli of composite composites was investigated and an optimal balance of composite properties was achieved at a lower percentage of sEPR-G-MA and medium BF loading level.
Abstract: Mechanical properties and morphologies of HDPE/bamboo flour (BF) composites modified with two maleated ethylene/propylene elastomers (EPR-g-MA) and one maleated polyethylene (PE-g-MA) were investigated. The concentration of each modifier varied between 0 and 8.3 wt% based on the total composite weight. The highest values in strengths and moduli were achieved for the composites containing PE-g-MA, whereas the use of semi-crystalline EPR-g-MA (sEPR-g-MA) led to the maximum impact strength. However, the presence of amorphous EPR-g-MA (aEPR-g-MA) reduced strengths of the resultant composites. The impact toughness of the aEPR-g-MA modified composites initially increased with aEPR-g-MA loading up to 2.9 wt%, and then gradually decreased beyond this level. By simultaneously incorporating both PE-g-MA and EPR-g-MA, the strength–toughness balance of the final composites was optimized. The optimal balance of composite properties was achieved at lower percentage of sEPR-g-MA and medium BF loading level. Dynamic mechanical analysis (DMA) and morphology observations well substantiated the above-mentioned mechanical results. It was found that suitable interfacial adhesion and easiness of interlayer cavitations between HDPE and BF is beneficial to initiate massive matrix yielding in the composites, thereby achieving satisfactory impact strength.
124 citations
Cites background from "Mechanical Properties of Polymers a..."
...52 vol % [58], the formation of BF network due to their partial contact may be responsible for such a remarkable increase at the higher loading level....
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...adhesion between the components and the improvement of the nature of the matrix–filler interface [58]....
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TL;DR: In this paper, the effect of the curing temperature on the physical and mechanical properties of three structural adhesives was investigated using an in-house developed apparatus and the results showed that the strength and stiffness of the adhesive increase as the cure temperature increases and the T g is higher than the cure temperatu...
Abstract: This paper describes the influence of the curing temperature on the physical and mechanical properties of three structural adhesives. This work was undertaken to improve the understanding of the effect of curing temperature in the glass transition temperature, T g , and stiffness of epoxy adhesives. The mechanical properties (Young's modulus and yield strength) of the adhesives were measured in bulk specimens. T g was measured by a dynamic mechanical analysis using an in-house developed apparatus. The curing process was the same for all tests, consisting of a curing stage followed by a post cure stage. The initial stage was performed at different temperatures. T g and the mechanical properties was found to vary as a function of the cure temperature of the adhesive. When cured below the cure temperature, T cure , at which the T g of the fully cured network, T g ∞, is achieved, the strength and stiffness of the adhesive increase as the cure temperature increases and the T g is higher than the cure temperatu...
123 citations
Cites background from "Mechanical Properties of Polymers a..."
...This is because the activation energy for conformational changes is lower and the conformational changes can take place at lower temperatures [7,8]....
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TL;DR: In this paper, atrazine-sensitive conductimetric sensors were designed using molecularly imprinted polymer membranes, which were prepared by copolymerization of methacrylic acid and a crosslinker, tri(ethylene glycol) dimethacrylate.
Abstract: Atrazine-sensitive conductimetric sensors were designed using molecularly imprinted polymer membranes. Membranes containing artificial recognition sites for atrazine were prepared by copolymerization of methacrylic acid and a cross-linker, tri(ethylene glycol) dimethacrylate, in the presence of atrazine as a template. In order to improve the flexibility and mechanical stability of the membranes, oligourethane acrylate was added to the mixture of monomers. The recognition sites complementary to atrazine were formed in the membranes after extraction of the template molecules with ethanol. Alternatively, reference polymer membranes were prepared with the same monomers but without the template. The responses of the membranes prepared with and without the template were monitored conductimetrically. The membranes prepared in the presence of atrazine showed significantly stronger responses to atrazine than to analogous compounds (triazine, simazine, prometryn). The response time was 6–15 min depending on the membrane thickness. The effect of the membrane composition and the porogen concentration on the magnitude of the conductimetric responses was also investigated. With the sensor designed here, the detection of the atrazine at concentrations down to 5 nmol dm–3 was demonstrated. During a 6 month period, the sensitivity of the molecularly imprinted membranes to atrazine was found to remain constant.
122 citations
TL;DR: A comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics provides mechanistic insight into fracture modes in this class of materials.
Abstract: This paper describes a comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics. In the first method, the film is supported by water (film-on-water, FOW), and a stress–strain curve is obtained using a direct tensile test. In the second method, the film is supported by an elastomer (film-on-elastomer, FOE), and is subjected to three tests to reconstruct the key features of the stress–strain curve: the buckling test (tensile modulus), the onset of buckling (yield point), and the crack-onset strain (strain at fracture). The specimens used for the comparison are four poly(3-hexylthiophene) (P3HT) samples of increasing molecular weight (Mn = 15, 40, 63, and 80 kDa). The methods produced qualitatively similar results for mechanical properties including the tensile modulus, the yield point, and the strain at fracture. The agreement was not quantitative because of differences in mode of loading (tension vs comp...
122 citations