The Role of Functional Polymers in Ground Rubber Tire-Polyethylene Composite

1992 ◽  
Vol 65 (5) ◽  
pp. 908-916 ◽  
Author(s):  
P. Rajalingam ◽  
W. E. Baker

Abstract The impact energies of different polyethylene-ground rubber tire (GRT) composites were investigated. All the thermoplastic composites were prepared on a Haake Buchler batch mixer and injection molded test specimens were tested on Rheometrics drop weight instrumented impact tester. Addition of small amounts of functional polymers increases the impact energy of the polyethylene-GRT composite as much as 60%. The percent improvement in the impact energy for linear low density polyethylene (LLDPE) and the composites prepared from them is greater than for the corresponding high density polyethylene (HDPE) composites. Precoating of GRT particles with ethylene-acrylic acid (EAA) copolymers improves the impact energy of the composite, whereas precoating with the other functional polymers does not. An attempt has been made to identify the role of the functional polymers as to whether they act as toughening agents for the polyethylene matrix or coupling agent at the polyethylene-GRT interface. The results show the increase in impact energy resulting from the addition of styrene block copolymers is due to toughening of the polyethylene matrix while the reactive ethylene copolymers increase the impact energy by a coupling action with GRT.

1993 ◽  
Vol 66 (4) ◽  
pp. 664-677 ◽  
Author(s):  
P. Rajalingam ◽  
J. Sharpe ◽  
W. E. Baker

Abstract Thermoplastic composites containing different Ground Rubber Tire (GRT) materials, Linear Low Density Polyethylene (LLDPE) and, in some case, a coupling agent (IB‘E’, an ethylene glycidyl methacrylate copolymer) were prepared by melt blending. The impact energies of all the thermoplastic composites (normally containing 40 wt % GRT) were evaluated using an instrumented impact tester. The effects of the GRT particle-size, particle size distribution and shape, the mode of grinding, and the oxygen surface concentration were analyzed. The wet-ambient-ground GRT based composites show higher surface oxidation and give better impact energy than cryo-ground and normal air-ground GRT based composites. Smaller GRT particle size results in a small increase in the impact property of the composite and a greater influence on the melt processability of the composites. Of the different GRT surface modification techniques studied for improved composite interfacial adhesion and impact properties the composites from electron beam radiation treated GRT yield higher increases in impact energy in comparison to corona and plasma treated GRT based composites.


Author(s):  
Mingyu Sun ◽  
Xuemin Wang ◽  
R.D.K. Misra

700 MPa grade Ti and Nb-Ti microalloyed steels produced by thermo-mechanical control rolled processes (TMCP) were studied to elucidate texture that contributes to delamination and consequent impact toughness. The microstructure of Ti and Nb-Ti steels consisted of ferrite and bainite. Compared with Ti steel, Nb-Ti steel was characterized by a microstructure with finer ferrite and more bainite. The results from tensile and impact tests indicated that there is insignificant change in tensile properties, but toughness was greater in Nb-Ti steel compared with Ti steel. More severe delamination in Nb-Ti steel is attributed to stronger α-fiber (RD ||<110>) texture than Ti steel, especially {100}<110>, {113}<110> and {112}<110> texture. Typical cleavage river patterns were not observed on delaminated fracture surface, instead the cleavage fracture surface indicated some dimples. Interestingly, the impact energy of samples with delamination was greater than samples without delamination in the ductile–brittle transition region. The study suggests that delamination in the ductile–brittle transition zone may also be representative of high toughness.


Polimery ◽  
2017 ◽  
Vol 62 (7/8) ◽  
pp. 548-555 ◽  
Author(s):  
Eduard V. Prut ◽  
Lyubov A. Zhorina ◽  
Larisa V. Kompaniets ◽  
Dmitrii D. Novikov ◽  
Arkadii Ya. Gorenberg

2018 ◽  
Vol 18 (1) ◽  
pp. 6-20 ◽  
Author(s):  
V. Vassileva ◽  
H. Danninger ◽  
S. Strobl ◽  
Ch. Gierl-Mayer ◽  
R. de Oro Calderon ◽  
...  

Abstract Boron has been known to activate densification during sintering of ferrous powder compacts, though with risk of embrittlement. In the present study, specimens Fe-B and Fe-C-B prepared from standard atomized iron powder with addition of ferroboron Fe-21%B were sintered in different atmospheres, and the resulting microstructures and properties were studied. It showed that the activating effect of boron is observed during sintering in argon and in hydrogen while sintering in N2 containing atmospheres results in rapid deactivation of boron, through formation of stable BN. In hydrogen atmosphere, surface deboronizing was observed to considerable depth. Ar is chemically inert, but Ar trapped inside closed pores tends to inhibit further densification. The impact energy data indicated that the embrittling effect of boron is enhanced significantly by presence of carbon. In the fracture surfaces, transgranular cleavage fracture can be observed both at very low and high impact energy values.


2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.


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