Rheology of Blends of a Rodlike Polymer (PBO) and its Flexible Chain Analog

1989 ◽  
Vol 171 ◽  
Author(s):  
V. J. Sullivan ◽  
G. C. Berry
Keyword(s):  
Mechanical Properties ◽  
Steady State ◽  
Relaxation Spectrum ◽  
Dynamic Mechanical Properties ◽  
Flexible Chain ◽  
Miscible Blends ◽  
Recoverable Compliance ◽  
Viscosity Enhancement ◽  
And Storage ◽  
Rodlike Polymer

ABSTRACTRheological properties of isotropic solutions of rodlike poly(p-phenylene benzbisoxazole), PBO, flexible chain poly(2,5-benzoxazole), ABPBO, and their miscible blends in solution are described. Measurements include steady state properties (the viscosity and recoverable compliance as functions of shear rate), transient properties (the recoverable compliance), and dynamic mechanical properties (the loss and storage compliances as functions of frequency). The relaxation spectrum of the blends is broader than that for the rodlike chain, and tends to occur at longer times, reflecting a viscosity enhancement that occurs with the blends. The measured zero shear viscosities for rod and blend solutions are compared with predictions based on the model of Doi and Edwards.

Mechanical and Dynamic Mechanical Properties of Degradable Polyurethane Foams with PEG/PCL Mixed Soft Segments

2011 ◽  
Vol 183-185 ◽  
pp. 1611-1615 ◽  
Author(s):  
Jian Hua Wang ◽  
Shuen Liang ◽  
Yan Yan Wang ◽  
Chun Rong Tian ◽  
Xiu Li Zhao
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Compressive Strain ◽  
Dynamic Mechanical Properties ◽  
Polyurethane Foams ◽  
Elongation At Break ◽  
Dynamic Mechanical ◽  
Soft Segments ◽  
And Storage

Polyurethane (PU) with mixed poly(ethylene glycol) / poly(ε-caprolactone) (PEG/PCL) soft segments is a representatively kind of degradable polyurethane material. Polyurethane foams (PUF) with mixed PEG/PCL soft segments were synthesized by using one pot method, and their mechanical and dynamic mechanical properties were investigated. Influences of PEG/PCL weight ratio and molecular weight of soft segments on PUF's mechanical and dynamic mechanical properties were studied. The results showed that: with increasing content of PCL, PUF's tensile strength, elongation at break, stress at certain tensile/compressive strain and storage modulus increased gradually; with increasing molecular weight of soft segment, PUF's elongation at break increased, but tensile strength, stress at certain tensile/compressive strain and storage modulus all decreased accordingly; glass transition temperature (Tg) of PUF with various soft segments decreased according to the following sequence: PEG-400, PCL-210N, PEG-1000 and PTMG1000; loss factor of PUF with PEG/PCL mixed soft segments was higher than that of PUF with individual PEG or PCL soft segments.

scholarly journals Casein/Apricot Filler in the Production of Flame-Retardant Polyurethane Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3620
Author(s):  
Sylwia Członka ◽  
Agnė Kairytė ◽  
Karolina Miedzińska ◽  
Anna Strąkowska
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Dynamic Mechanical Properties ◽  
Uniform Structure ◽  
Thermal And Mechanical Properties ◽  
Mechanical Performances ◽  
Polyurethane Composites ◽  
Natural Combination ◽  
The Impact ◽  
And Storage

Polyurethane (PUR) composites reinforced with 1, 2, and 5 wt.% of apricot filler modified with casein were synthesized in the following study. The impact of 1, 2, and 5 wt.% of casein/apricot filler on the cellular structure and physico-mechanical performances of reinforced PUR composites were determined. It was found that the incorporation of 1 and 2 wt.% of casein/apricot filler resulted in the production of PUR composites with improved selected physical, thermal, and mechanical properties, while the addition of 5 wt.% of casein/apricot filler led to some deterioration of their physico-mechanical performance. The best results were obtained for PUR composites reinforced with 2 wt.% of casein/apricot filler. Those composites were characterized by a uniform structure and a high content of closed cells. Compared with the reference foam, the incorporation of 2 wt.% of casein/apricot filler resulted in improvement in compressive strength, flexural strength, impact strength, and dynamic mechanical properties—such as glass transition temperature and storage modulus. Most importantly, PUR composites showed better fire resistance and thermal stability due to the good thermal performance of casein. The main aim of this article is to determine the influence of the natural combination of the apricot filler and casein on the mechanical properties and flammability of the obtained composites.

RECLAIMING OF GROUND RUBBER TIRE BY SAFE MULTIFUNCTIONAL RUBBER ADDITIVES: II VIRGIN NATURAL RUBBER/RECLAIMED GROUND RUBBER TIRE VULCANIZATES

2014 ◽  
Vol 87 (1) ◽  
pp. 152-167 ◽  
Author(s):  
Swapan Kumar Mandal ◽  
Md Najib Alam ◽  
Kumarjyoti Roy ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Thermo Gravimetric Analysis ◽  
Dynamic Mechanical Properties ◽  
Gravimetric Analysis ◽  
Rubber Content ◽  
Rubber Tire ◽  
Ground Rubber ◽  
Cure Time ◽  
And Storage

ABSTRACT Mechanochemically reclaimed ground rubber tire (GRT) was revulcanized in combination with virgin natural rubber (NR). The NR/GRT vulcanizates with GRT content 20–50 wt% were prepared and studied. Reclaiming of GRT was successfully carried out by tetra benzyl thiuram disulfide (TBzTD) in the presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaimed GRT blend were studied. Increasing the reclaimed rubber (RR) content in the blend decreases the optimum cure time without altering the scorch time. The effect of carbon black was studied in NR/RR (80/20) blend vulcanizate for the ultimate use of NR/RR blend vulcanizate. Aging characteristics of different NR/RR blends were evaluated. The swelling behavior, thermo-gravimetric analysis, and dynamic mechanical properties of NR/RR blend vulcanizates were examined. The equilibrium swelling of the NR vulcanizates was reduced with increasing reclaimed rubber content. Thermal stability of the blend vulcanizates was increased with increase in reclaimed rubber content. The elastic and storage modulus of the NR/RR vulcanizates improved with increasing reclaimed rubber content. Scanning electron microscopy studies further indicate the coherency and homogeneity in the NR/RR vulcanizate.

Polyurethanes based on hydroxylated rapeseed oil: thermal and dynamic mechanical properties

2015 ◽  
Vol 37 (2) ◽  
pp. 162-167
Author(s):  
V.A. Vilensky ◽  
◽  
L.V. Kobrina ◽  
S.V. Riabov ◽  
Y.Y. Kercha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rapeseed Oil ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical
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