Effect of carbon allotropes on foam formation, cure characteristics, mechanical and thermal properties of NRF/carbon composites

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.

2021 ◽  
Vol 876 ◽  
pp. 13-18
Author(s):  
Pollawat Charoeythornkhajhornchai ◽  
Jinjuta Owakusumsirisakul ◽  
Wuttinun Khamloet ◽  
Pattarawan Nungjumnong

Natural rubber foam is used in industries as a gasket and insulation product. Dimensional expansion of specimen is the crucial problem of rubber foam specimen, especially in the automotive parts assembly. This work aims to understand the behavior of natural rubber foam (NRF)/carbon composites on microstructure and properties of NRF before being used. Carbon was synthesized from durian bark which was the agricultural waste that had the potential for using as reinforcing filler. The result showed the fast sulfur vulcanization rate with small bubble size at high amount of carbon. In addition, the young modulus of NRF/carbon composites increased with increasing carbon content.


2013 ◽  
Vol 844 ◽  
pp. 334-337 ◽  
Author(s):  
Thiranan Thuechart ◽  
Wirunya Keawwattana

Study the effect of kaolin clay as a synergistic agent on flame retardancy and thermal degradation in natural rubber based on intumescent flame retardant (IFR); consisting of ammonium polyphosphate (APP) as acid source, pentaerythritol (PER) as a carbonization agent and melamine (ME) as a blowing agent was undertaken. The intumescent was examined at different loading (60, 80 and 100 phr). Kaolin clay was incorporated into flame retardant at four different concentrations (0.5, 1.0, 1.5 and 2.0 wt% of flame retardant) to investigate the synergism between the flame retardant materials. The flammability and thermal degradation of composites were characterized by UL-94 rating (vertical burning) test, cone calorimeter (CONE) and thermogravimetric analysis (TGA). All composites could meet the UL94V-0 standard. A synergist effect was observed when kaolin clay is used in combination with the intumescent flame-retardant through the TGA and CONE results. Moreover Scanning Electron Microscope (SEM) was done for the char morphology.


2015 ◽  
Vol 804 ◽  
pp. 25-29 ◽  
Author(s):  
Wanlop Harnnarongchai ◽  
Kantima Chaochanchaikul

The sound absorbing efficiency of natural rubber (NR) foam is affected by the cell morphology of foam. Potassium oleate (K-oleate) and sodium bicarbonate (NaHCO3) were used as blowing agents to create open-cell foam. Amounts of the blowing agent were varied from 0.5 to 8.0 part per hundred of rubber (phr) to evaluate cell size and number of foam cell as well as sound adsorption coefficient of NR foam. The NR foam specimens were prepared using mould and air-circulating oven for vulcanizing and foaming processes. The results indicated that K-oleate at 2.0 phr and NaHCO3 at 0.5 phr led to form NR foam with the smallest cell size and the largest number of foam cell. At low frequencies, the optimum sound adsorption coefficient of NR foam was caused by filling K-oleate 2 phr. However, that of NR foam at high frequencies was provided by 0.5 phr-NaHCO3 addition.


2012 ◽  
Vol 18 (3) ◽  
pp. 184-191 ◽  
Author(s):  
Natita Hamaviriyapornwattana ◽  
Narongrit Sombatsompop ◽  
Teerasak Markpin ◽  
Apisit Kositchaiyong ◽  
Ekachai Wimolmala

2021 ◽  
Vol 904 ◽  
pp. 441-446
Author(s):  
Nuchnapa Tangboriboon ◽  
Sarun Muntongkaw ◽  
Sompratthana Pianklang

Adding 0, 20, and 50 wt% natural-rubber latex compound into the plaster ceiling matrix affected to increase the physical-mechanical-thermal performance properties of plaster ceiling composites. Adding 50 wt% natural rubber latex compound into plaster composites can increase the superior adhesion of the nail-tensile resistance equal to 57.54 N and decrease thermal conductivity equal to 0.0634 W/m.K. In addition, adding natural rubber latex compounds into plaster composites can reduce water solubility, brittleness, impact, and cost of energy consumption due to the exterior temperature. Adequate thermal insulation for roofing, ceiling, and wall systems also reduces radiative losses that chill occupants in cold weather, and reduce interior surface temperatures in the summer, thereby optimizing the comfort of building occupants. The mechanical and thermal properties of plaster composites were investigated by using a Universal Testing Machine (UTM) and heat flow meter, respectively, measured according to TIS 1211-50, TIS 219-2522, and ASTM C518.


2021 ◽  
Author(s):  
IVAN GALLEGOS ◽  
JOSHUA KEMPPAINEN ◽  
SAGAR U. PATIL ◽  
PRATHAMESH DESHPANDE ◽  
JACOB GISSINER ◽  
...  

Carbon-carbon composites (CCCs) widely used in the aerospace and automotive industries due to their excellent mechanical and thermal properties. Phenolic resins have a relatively high carbon yield, which makes them a suitable candidate for CCCs manufacturing. Molecular Dynamics (MD) can further reduce costs by predicting properties of a material before manufacturing and testing. In the present work, a Molecular Dynamics (MD) model of a crosslinked phenolic resin was developed to predict mechanical properties by implementing the fix bond/react algorithm in LAMMPS. The predicted mass density (ρ) and Young’s Modulus (E) agree well with experimental values and highlights the validity of the topologybased approach to building stable molecular models of phenolic resins.


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