Effect of acrylic block copolymer on the fracture toughness and glass transition temperature of carbon fabric reinforced 180°C cure-epoxy composites

2017 ◽  
Vol 659 (1) ◽  
pp. 15-22
Author(s):  
Kyung Hoon Choi ◽  
Dae-Geon Yoo ◽  
Gue-Hyun Kim ◽  
Chang-Sik Ha
2018 ◽  
Vol 59 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Katja Utaloff ◽  
Martin Heinz Kothmann ◽  
Michael Ciesielski ◽  
Manfred Döring ◽  
Thomas Neumeyer ◽  
...  

Author(s):  
Y. Kochergin ◽  
A. Nosova ◽  
T. Kravchuk ◽  
T. Grigorenko ◽  
V. Zolotareva

A method for the synthesis of a complex based on an organic tin halide – dibutylol dibromide – and a aminophenol hardener of the UP-583 brand has been developed. It is found that samples cured with a complex hardener at room temperature are characterized by lower values of tensile strength, elastic modulus and glass transition temperature compared to samples cured with the original hardener UP-583. The values of strain at break are approximately the same for both hardeners. After heat treatment, the strength and modulus values for samples containing the complex sharply increase, as a result of which they are superior to samples based on UP-583. The deformation capacity does not change much, the glass transition temperature increases after heating, but remains significantly lower than for samples cured with the original UP-583. The observed change in the deformation and strength properties of samples during their exposure in a liquid medium is explained by the superposition of the effects of plasticization and re-hardening of epoxy polymers. At low exposure times, the action of the sorbed moisture is mainly aimed at weakening the intermolecular interaction in the sample. In result, its strength decreases and deformability increases. At large values of exposure times, when the amount of sorbed water becomes sufficiently large and a fairly intense molecular mobility develops, pre-hardening processes prevail, leading to an increase in the cross-linking density and, to a decrease in the deformation ability and an increase in the strength index. It is shown that epoxy composites containing a complex hardener are characterized by good performance in the water environment, increased resistance to the development of fungi and mold, as well as better fire resistance. The studied polymers are promising for obtaining antifouling coatings based on them for hydraulic equipment, sea and river vessels.


2019 ◽  
Vol 10 (23) ◽  
pp. 3135-3145 ◽  
Author(s):  
Lewis C. Chambers ◽  
Yun Huang ◽  
Kevin S. Jack ◽  
Idriss Blakey

Spatially controlling self-assembly of block copolymer thin films through photoinduced molecular interactions that significantly impact on the glass transition temperature.


Soft Matter ◽  
2018 ◽  
Vol 14 (44) ◽  
pp. 8895-8911 ◽  
Author(s):  
Robert M. Elder ◽  
Tyler R. Long ◽  
Erich D. Bain ◽  
Joseph L. Lenhart ◽  
Timothy W. Sirk

We use molecular simulations and experiments to rationalize the properties of a class of networks based on dicyclopentadiene (DCPD), a polymer with excellent fracture toughness and a high glass transition temperature (Tg), copolymerized with 5-norbornene-2-methanol (NBOH).


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 259 ◽  
Author(s):  
Sung-Hwan Jang ◽  
Long-Yuan Li

This paper reported the effect of high temperature on the electro-mechanical behavior of carbon nanotube (CNT) reinforced epoxy composites. CNT/epoxy composites were fabricated by dispersing CNTs in the epoxy matrix using a solution casting method. Electrical conductivity measurements obtained for the CNT/epoxy composites indicated a steadily increasing directly proportional relationship with CNT concentration with a percolation threshold at 0.25 wt %, reaching a maximum of up to 0.01 S/m at 2.00 wt % CNTs. The electro-mechanical behavior of CNT/epoxy composites were investigated at a room temperature under the static and cyclic compressive loadings, resulting that the change in resistance of CNT/epoxy composites was reduced as increasing CNT concentration with good repeatability. This is due to well-networked CNTs conducting pathways created within the solid epoxy matrix observed by scanning electron microscopy. Temperature significantly affects the electro-mechanical behavior of CNT/epoxy composites. In particular, the electro-mechanical behavior of CNT/epoxy composites below the glass transition temperature showed the similar trend with those at room temperature, whereas the electro-mechanical behavior of CNT/epoxy composites above the glass transition temperature showed an opposite change in resistance with poor repeatability due to unstable CNT network in epoxy matrix.


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