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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 paper, the tensile behavior of polypropylene and 40 w% talc-filled polypropylenes was determined at four different temperatures (21.5, 50, 75 and 100°C) and three different strain rates (0.05, 0.5 and 5 min -1 ).
Abstract: The tensile behavior of unfilled and 40 w% talc-filled polypropylene has been determined at four different temperatures (21.5, 50, 75 and 100°C) and three different strain rates (0.05, 0.5 and 5 min -1 ). Experimental results showed that both unfilled and talc-filled polypropylenes were sensitive to strain rate and temperature. Stress-strain curves of both materials were nonlinear even at relatively low strains. The addition of talc to polypropylene increased the elastic modulus, but the yield strength and yield strain were reduced. The temperature and strain rate sensitivities of these materials were also different. An energy-activated, rate sensitive Eyring equation was used to predict the yield strength of both materials. It is shown that both activation volume and activation of energy increased with the addition of talc in polypropylene.
69 citations
TL;DR: In this article, the transcrystallinity of an aramid fiber-reinforced nylon 66 microcomposite was studied using dynamic mechanical thermal analysis and the results showed that the viscoelastic energy damping of the trans-crystalline layer, tanδ tc = 0.064, is smaller while the elastic modulus, E ′ tc = 4.6GPa, is higher compared with the crystallized matrix.
69 citations
TL;DR: In this article, the ionic conductivity of chitosan-based ion-immobilized electrolyte composite membranes was investigated using impedance spectroscopy, and the results suggest that in order to ensure the composite membranes to have desired mechanical properties and higher conductivity, and to be possibly used in an alkaline fuel cell, the ratio of glutaraldehyde to chitosa-polysilicon polysilicon (GSP) should be selected between 4 and 5 W.% and the content of potassium hydroxide loaded inside the inner layer should be controlled below
68 citations
TL;DR: In this paper, the Nicolai and Narkis equation was used to predict the tensile strength of composites containing hydroxyapatite, which was then used for weak filler adhesion.
Abstract: Summary: Hydroxyapatite, chitosan, and aliphatic polyester were compounded using a twin-screw extruder. The polyesters include poly(e-caprolactone) (PCL), poly(lactic acid) , poly(butylene succinate) (PBS), and poly(butylene terephthalate adipate). The mass fraction of chitosan ranged from 17.5 to 45%, while that of HA ranged from 10 to 30%. These blends were injection molded and evaluated for thermal, morphological, and mechanical properties. The addition of hydroxyapatite decreased the crystallinity in chitosan/PBS blends, while in blends containing chitosan/PCL, the crystallinity increased. Addition of hydroxyapatite significantly decreased the tensile strength and elongation of polyester/ hydroxyapatite composites as well as chitosan/polyester/ hydroxyapatite composites with elongations undergoing decreases over an order of magnitude. The tensile strength of the composite was dictated by the adhesion of HA to the chitosan/polyester matrix. The tensile strength of composites containing hydroxyapatite could be predicted using the Nicolai and Narkis equation for weak filler adhesion (K � 1.21). Tensile-fractured and cryogenically-fractured surface indicates extensive debonding of hydroxyapatite crystals from the matrix, indicating weak adhesion. The adhesion of hydroxyapatite was higher for pure polyester than those containing chitosan and polyester. The modulus of the composites registered modest increase. The two main diffraction peaks observed using WAXS are unaffected by the amount of chitosan or hydroxyapatite.
68 citations
Cites background from "Mechanical Properties of Polymers a..."
...Predictive equations for tensile strength have been reported([33]) and can be used to present a qualitative analysis regarding the adhesion between the filler and the polyester....
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01 Jan 1998
TL;DR: In this paper, several alcohols and water were added to diethylene-glycol-divinyl-ether (DVE2) or triethylene- glycol-DIVINITY-THEURO-THIOT (THEET) in order to investigate their influence on the cationic photopolymerization in the presence of triarilsulfonium hexafluorophosfate as photoinitiator.
Abstract: Abstract Several alcohols (n-butanol, 2-propanol, 2-phenyl-2-propanol) and water were added to diethylene-glycol-divinyl-ether (DVE2) or triethylene-glycol-divinyl-ether (DVE3) in order to investigate their influence on the cationic photopolymerization in the presence of triarilsulfonium hexafluorophosfate as photoinitiator. Until 5% w/w concentration, the alcohols do not show any influence on the rate of polymerization, but they increase the final double bond conversion indicating a plasticization effect. Water causes a decrease of the rate of polymerization and an increase of the final double bond conversion. DSC and DMTA analyses show that the presence of the additives decreases the Tg of the UV-cured products. The results are interpreted on the basis of a chain transfer reaction involving -OH groups.
68 citations