scholarly journals Thermo-expandable microcapsule as a blowing agent for producing thermoplastic elastomer vulcanized syntactic foam

2020 ◽  
Author(s):  
M. Riou ◽  
G. Ausias ◽  
T. Gaudry ◽  
J.-M. Veillé ◽  
J. Férec ◽  
...  
2018 ◽  
Vol 136 (8) ◽  
pp. 47358
Author(s):  
Hyo Jae Kong ◽  
Seung Hak Lee ◽  
Dong Gun Kim ◽  
Hyo Jun Kim ◽  
Gun Wook Park ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Safia Merabet ◽  
Farid Riahi ◽  
Abdelmalek Douibi

The decomposition of azobisformamide (ABFA) blowing agent and its expansion in a soft grade of thermoplastic natural rubber composed of a 70/30 natural rubber (NR)/polypropylene (PP) was monitored using a Haake plasticorder. The aim of the study was to evaluate the effect of different concentrations of the blowing agent and to investigate its eventual interactions with a sulfur-based curing system that was used for the dynamic vulcanization. The plastograms allowed to detect variations in the initial mixing torque as well as the level of the final equilibrium torque for both unvulcanized and dynamically vulcanized blends. The plastograms of the dynamically vulcanized blends were characterized by the appearance of a second peak that corresponds to the crosslinking reaction which followed the blowing agent decomposition reaction. Since changing the order of the addition of the curatives with respect to the blowing agent did not cause any major effect on the general trend of the plastograms, it was concluded that the azobisformamide blowing agent did not alter the chemical action of the curatives and vice versa. The effects on the plastograms caused by variations in the blowing agent concentration were also reflected through the density measurements.


1989 ◽  
Author(s):  
R. W. Fletcher ◽  
H. W. Cheung

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 300 ◽  
Author(s):  
Bei Su ◽  
Ying-Guo Zhou ◽  
Bin-Bin Dong ◽  
Cao Yan

To improve the foaming behavior of a common linear polypropylene (PP) resin, polycarbonate (PC) was blended with PP, and three different grafted polymers were used as the compatibilizers. The solid and foamed samples of the PP/PC 3:1 blend with different compatibilizers were first fabricated by melt extrusion followed by injection molding (IM) with and without a blowing agent. The mechanical properties, thermal features, morphological structure, and relative rheological characterizations of these samples were studied using a tensile test, dynamic mechanical analyzer (DMA), scanning electron microscope (SEM), and torque rheometer. It can be found from the experimental results that the influence of the compatibility between the PP and PC phases on the foaming behavior of PP/PC blends is substantial. The results suggest that PC coupling with an appropriate compatibilizer is a potential method to improve the foamability of PP resin. The comprehensive effect of PC and a suitable compatibilizer on the foamability of PP can be attributed to two possible mechanisms, i.e., the partial compatibility between phases that facilitates cell nucleation and the improved gas-melt viscosity that helps to form a fine foaming structure.


2017 ◽  
Vol 90 (3) ◽  
pp. 550-561 ◽  
Author(s):  
Prithwiraj Mandal ◽  
Siva Ponnupandian ◽  
Soumyadip Choudhury ◽  
Nikhil K. Singha

ABSTRACT Thiol-ene modification of high vinyl content thermoplastic elastomeric styrene butadiene styrene (SBS) block copolymer (BCP) was carried out using different thiolating agents in toluene at 70 °C. 1H NMR analysis confirmed the participation of vinyl double bond in the thiol-ene modification reaction of SBS. Surface morphology of the block copolymers evaluated by atomic force microscopy analysis showed higher roughness after the thiol-ene reaction. The thiol-modified SBS block copolymer showed better adhesion strength and oil resistance properties than the pristine SBS.


Author(s):  
A Hamdi ◽  
A Boulenouar ◽  
N Benseddiq

No unified stress-based criterion exists, in the literature, for predicting the rupture of hyperelastic materials subjected to mutiaxial loading paths. This paper aims to establish a generalized rupture criterion under plane stress loading for elastomers. First, the experimental set up, at breaking, including various loading modes, is briefly described and commented. It consists of uniaxial tests, biaxial tests and pure shear tests, performed on different rubbers. The used vulcanizate and thermoplastic rubber materials are a Natural Rubber (NR), a Styrene Butadiene Rubber (SBR), a Polyurethane (PU) and a Thermoplastic elastomer (TPE). Then, we have investigated a new theoretical approach, based upon the principal stresses, to establish a failure criterion under quasi-static loadings. Thus, we have proposed a new analytical model expressed as a function of octahedral stresses. Quite good agreement is highlighted when comparing the ultimate stresses, at break, between the experimental data and the prediction of the proposed criteria using our rubber-like materials.


2021 ◽  
Vol 26 ◽  
pp. 102027
Author(s):  
Elnaz Esmizadeh ◽  
Ali Vahidifar ◽  
Sahar Shojaie ◽  
Ghasem Naderi ◽  
Mohammad Reza Kalaei ◽  
...  

2020 ◽  
pp. 0021955X2097954
Author(s):  
Pollawat Charoeythornkhajhornchai ◽  
Wutthinun Khamloet ◽  
Pattharawun Nungjumnong

Natural rubber composite foam with carbon such as carbon black (CB), carbon synthesized from durian bark (CDB), graphite (GPT), graphene oxide (GO), graphene (GPE) and multi-walled carbon nanotubes (MWCNT) was studied in this work to investigate the relationship between foam formation during decomposition of chemical blowing agent mechanism and crosslink reaction of rubber molecules by sulphur. Natural rubber composite foam with carbon particle was set at 3 parts per hundred of rubber (phr) to observe the effect of carbon allotropes on foam formation with different microstructure and properties of natural rubber composite foam. The balancing of crosslink reaction by sulphur molecules during foam formation by the decomposition of chemical blowing agent affects the different morphology of natural rubber foam/carbon composites leading to the different mechanical and thermal properties. The result showed the fastest cure characteristics of natural rubber foam with 3 phr of graphene (NRF-GPE3) which was completely cure within 6.55 minutes (tc90) measured by moving die rheometer resulting in the smallest bubble diameter among other formulas. Moreover, natural rubber foam with 3 phr of MWCNT (NRF-MWCNT3) had the highest modulus (0.0035 ± 0.0005 N/m2) due to the small bubble size with high bulk density. In addition, natural rubber foam with 3 phr of GPT (NRF-GPT3) had the highest thermal expansion coefficient (282.12 ± 69 ppm/K) due to high amount of gas bubbles inside natural rubber foam matrix and natural rubber foam with 3 phr of GO (NRF-GO3) displayed the lowest thermal conductivity (0.0798 ± 0.0003 W/m.K) which was lower value than natural rubber foam without carbon filler (NRF). This might be caused by the effect of bubble diameter and bulk density as well as the defect on surface of graphene oxide compared to others carbon filler.


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