A modified polyurethane elastomer using polyfunctional HTPB synthesized by in-situ nitroxide mediated polymerization of 1,3-butadiene

2012 ◽  
Vol 32 (6-7) ◽  
pp. 425-434
Author(s):  
Hassan Rezaei Haghighat ◽  
Mehdi Barikani ◽  
Jalil Morshedian
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Properties ◽  
Polyurethane Elastomer ◽  
Dynamic Mechanical ◽  
High Degree ◽  
Nitroxide Mediated Polymerization ◽  
Oligomeric Product ◽  
Thermal Stability Of

Abstract In-situ nitroxide mediated polymerization (NMP) of 1,3-butadiene was carried out in the presence of tetraethylenepentamine (TEPA) as a tri-functional nitroxide precursor, which furnished a high degree of hydroxy functionality. The multi-modal molar mass distribution of the product was elucidated by reductive hydrolyzation of the oligomeric product. The new polyfunctional hydroxyl-terminated polybutadiene (PFHTPB) was characterized and used in preparation of an HTPB-based polyurethane (PU). The effects of this new HTPB on mechanical and dynamic-mechanical properties of its corresponding polyurethane elastomer were studied. The mechanical and dynamic-mechanical characterization of the elastomer was evaluated by tensile and dynamic mechanical thermal analysis (DMTA) tests. A significant enhancement in mechanical properties of the elastomeric product with a small increase in the glass transition temperature was achieved using PFHTPB. In addition, there was a significant decrease in loss of the tangent value over the use of PFHTPB, compared to industrial HTPB, due to an efficient increase in crosslink density of the PFHTPB-based PU elastomer. The thermal stability of PFHTPB-based PU was comparable with its corresponding HTPB-based PU elastomer.

Fabrication of bionanocomposites reinforced with hemp nanocellulose and evaluation of their mechanical, thermal and dynamic mechanical properties

2021 ◽  
pp. 146442072110046
Author(s):  
SS Rana ◽  
MK Gupta
Keyword(s):  
Mechanical Properties ◽  
In Situ Polymerization ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
X Ray Diffraction ◽  
Dynamic Mechanical ◽  
Hemp Fibres ◽  
Polymerization Method

The present study aims to fabricate the epoxy-based bionanocomposites reinforced with hemp nanocellulose and the evaluation of their mechanical, thermal and dynamic mechanical properties. Nanocellulose from hemp fibres was isolated via the chemo-mechanical method and its bionanocomposites were prepared using the in situ polymerization method. Although many researchers have reported studies on the preparation and characterization of bionanocomposites however, studies on the mechanical, thermal, and dynamic mechanical properties of epoxy-based bionanocomposites reinforced with hemp nanocellulose are still unreported. The mechanical properties (i.e. tensile, flexural, hardness, and impact) and dynamic mechanical properties (i.e. glass transition temperature, damping behaviour, storage, and loss modulus) of the developed bionanocomposites were investigated. Further, the crystalline behaviour and thermal stability were also studied using the X-ray diffraction and thermogravimetric analysis techniques, respectively. The results revealed that an addition of nanocellulose considerably improved the mechanical, thermal, and viscoelastic properties of the bionanocomposites. As much as 52.17%, 48.17%, 89.08%, and 15.67% improvements in the tensile strength, flexural strength, impact strength, and hardness, respectively, for the 2 wt.% nanocellulose composites were found over the epoxy matrix.

Outstanding strengthening behavior and dynamic mechanical properties of in-situ Al–Al3Ni composites by Cu addition

2020 ◽  
Vol 189 ◽  
pp. 107891 ◽  
Author(s):  
Jeong Tae Kim ◽  
Viktor Soprunyuk ◽  
Niraj Chawake ◽  
Yong Hui Zheng ◽  
Florian Spieckermann ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical
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