Dynamic-Mechanical Study of the Dynamics of Polymer Blends near the Glass Transition

1995 ◽  
Vol 28 (8) ◽  
pp. 2693-2699 ◽  
Author(s):  
A. Sanchis ◽  
M. G. Prolongo ◽  
R. M. Masegosa ◽  
R. G. Rubio
Keyword(s):  
Glass Transition ◽  
Polymer Blends ◽  
Dynamic Mechanical ◽  
Mechanical Study

Dynamic mechanical properties of crystalline polymer blends. The influence of interface and orientation

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrzej Galeski
Keyword(s):  
Glass Transition ◽  
Polymer Blends ◽  
Amorphous Phase ◽  
Molecular Orientation ◽  
Temperature Shift ◽  
Crystalline Polymer ◽  
Intensity Change ◽  
Relaxation Processes ◽  
Dynamic Mechanical ◽  
Compatibilized Blends

AbstractModification of the interface changes the viscoelastic response of crystalline polymer blends. For incompatible systems, usually one or more additional tan δ (mechanical loss) peaks appear which reflect the embrittlement of the material. Upon proper compatibilization, the additional peaks disappear and the material becomes tougher. The associated phenomena are explained and illustrated by a number of examples including polypropylene filled with calcium carbonate, polyethylene (PE) and polystyrene compatibilized blends, compatibilized blends of poly(ethylene terephthalate) (PET) with polyethylene as well as polyamide 6/polypropylene- graft-acrylic acid blends. Modes of deformation producing cavitation and cavity free deformation were applied to polymer blends in order to study the influence of molecular orientation and the presence of cavities. It is concluded that interfaces between blend components are weak elements of the blends even in the presence of a compatibilizer. Dynamic mechanical analysis (DMTA) evidenced the occurrence of interactions of the compatibilizer with blend components through temperature shift and intensity change of α, β and γ relaxation processes of polymer components. In oriented films of PET/high-density PE compatibilized blends, the chain segments in the amorphous phase of PET are oriented along machine direction. However, there is a significant anisotropy of chain packing in the plane perpendicular to the drawing direction - the pseudohexagonal packing of chain fragments being in register over the whole film. The PET amorphous phase exhibits anisotropy: DMTA studies show that the glass transition occurs at different temperatures while bending the film in different directions. The source of the ‘anisotropy’ in glass transition is the anisotropy of the amorphous phase: the pseudohexagonal packing and the orientation of chain segments. It is evident that the free volume and frozen fraction of the amorphous phase exhibit some degree of anisotropy. In highly compressed samples free of cavities, the glass transition temperature is shifted to higher temperature as compared to undeformed or drawn and cavitated blends. The shift is the result of high molecular orientation of the amorphous phase of matrix polymer and of the stabilization effect of unbroken interfaces in compressed samples.

Pressure influence on the glass transition of polymers and polymer blends

1994 ◽  
Vol 32 (5-6) ◽  
pp. 645-652 ◽  
Author(s):  
H. A. Schneider ◽  
B. Rudolf ◽  
K. Karlou ◽  
H. -J. Cantow
Keyword(s):  
Glass Transition ◽  
Polymer Blends

scholarly journals Replacement of metallic parts for polymer composite materials in motorcycle oil pumps

2016 ◽  
Vol 36 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Sandro Donnini Mancini ◽  
Antídio de Oliveira Santos Neto ◽  
Maria Odila Hilário Cioffi ◽  
Eduardo Carlos Bianchi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Glass Transition ◽  
Glass Fiber ◽  
Dynamic Mechanical Analysis ◽  
Mechanical Analysis ◽  
Neutral Medium ◽  
Element Analysis ◽  
Dynamic Mechanical ◽  
Oil Pump

A feasibility study was conducted to determine the use of polyphthalamide/glass-fiber and polyphthalamide/glass-fiber/polytetrafluoroethylene-based composites as substitutes for aluminum and steel, respectively, in the production of motorcycle oil pump parts (housing, shaft/inner gerotor and outer gerotor). New and used (80,000 km) oil pumps were subjected to performance tests, whose results indicated that the pressure and temperature of the used pump reached a maximum of 1.8 bar and 93℃, respectively. Thermogravimetric analysis indicated that the materials are stable at the maximum operating temperature, which is 20℃ lower than the minimum glass transition temperature obtained by dynamic mechanical analysis for both materials at the analyzed frequencies (defined after calculations based on rotations in neutral, medium and high gear). The pressure value was multiplied by a safety factor of at least 1.6 (i.e., 3 bar), which was used as input for a finite element analysis of the parts, as well as the elasticity modulus at glass transition temperatures obtained by dynamic mechanical analysis. The finite element analysis indicated that the von Mises stresses to which the composite parts were subjected are 7 to 50 times lower than those the materials can withstand. The results suggest that it is feasible to manufacture motorcycle oil pump parts with these composites.

scholarly journals Comparison of mathematical models to predict glass transition temperature of rice (cultivar IRGA 424) measured by dynamic mechanical analysis

2018 ◽  
Vol 6 (8) ◽  
pp. 2199-2209 ◽  
Author(s):  
M. Mercedes Bertotto ◽  
Analía Gastón ◽  
María J. Rodríguez Batiller ◽  
Pablo Calello
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Mathematical Models ◽  
Dynamic Mechanical Analysis ◽  
Rice Cultivar ◽  
Mechanical Analysis ◽  
Dynamic Mechanical

Dynamic mechanical behaviour of kevlar and carbon-kevlar hybrid fibre reinforced polymer composites

2020 ◽  
pp. 095440622097060
Author(s):  
Pragati Priyanka ◽  
Harlal Singh Mali ◽  
Anurag Dixit
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Composite Laminates ◽  
Mechanical Analysis ◽  
Textile Composites ◽  
Elastic Behaviour ◽  
Dynamic Mechanical

Comprehensive experimental results of dynamic mechanical analysis (DMA) of polymer reinforced textile composites are presented in the current investigation. Plain and 2x2 twill woven multilayer fabrics of monolithic kevlar and hybrid carbon-kevlar (C-K) are reinforced into the thermoset polymer matrix. Kevlar/epoxy and C-K/epoxy composite laminates are fabricated using an in-house facility of the vacuum-assisted resin infusion process. Variation of the visco-elastic behaviour (storage modulus, damping factor and glass transition temperature, Tg) along with time, temperature and frequency is studied for the composites. Dynamic mechanical analysis is performed under temperature sweep with frequency ranging from 1-50 Hz. Results depict the effect of inter yarn hybridisation of carbon with kevlar yarns on the storage modulus, damping performance, and creep behaviour of dry textile composites. Temperature swept dynamic characterisation is also performed to evaluate the degradation and damping performance of the composite laminates soaked in the deionised water at glass transition temperature Tg, ½ Tg, and ¾ Tg. The morphological study has been performed post the dynamic mechanical analysis using field emission scanning electron microscope.

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