scholarly journals Tribological Performance and Thermal Stability of Nanorubber-Modified Polybenzoxazine Composites for Non-Asbestos Friction Materials

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2435
Author(s):  
Chanchira Jubsilp ◽  
Jakkrit Jantaramaha ◽  
Phattarin Mora ◽  
Sarawut Rimdusit

Asbestos-free friction composite based on ultrafine full-vulcanized acrylonitrile butadiene rubber particles (UFNBRPs)-modified polybenzoxazine was successfully developed. The UFNBRPs-modified polybenzoxazine friction composite was characterized for chemical, tribological, and mechanical properties as well as thermal stability. The UFNBRPs not only act as a filler to reduce noise in the friction composites due to their suitable viscoelastic behaviors but also play a key role in friction modifiers to enhance friction coefficient and wear resistance in the polybenzoxazine composites. The chemical bonding formation between UFNBRPs and polybenzoxazine can significantly improve friction, mechanical, and thermal properties of the friction composite. The outstanding tribological performance of the friction composite under 100–350 °C, i.e., friction coefficients and wear rates in a range of 0.36–0.43 and 0.13 × 10−4–0.29 × 10−4 mm3/Nm, respectively, was achieved. The high flexural strength and modulus of the friction composite, i.e., 61 MPa and 6.4 GPa, respectively, were obtained. The friction composite also showed high thermal stability, such as 410 °C for degradation temperature and 215 °C for glass transition temperature. The results indicated that the obtained UFNBRPs-modified polybenzoxazine friction composite meets the industrial standard of brake linings and pads for automobiles; therefore, the UFNBRPs-modified polybenzoxazine friction composite can effectively be used as a replacement for asbestos-based friction materials.

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vijay R. ◽  
Manoharan S. ◽  
Nagarajan S. ◽  
Lenin Singaravelu D.

Purpose The purpose of this study is to deals with the effect of premixed dual metal sulfides (tin disulfide + iron disulfide) as a replacement for antimony trisulfide on the tribological performance of brake friction materials. Design/methodology/approach In this study, brake friction materials were developed by using premixed dual metal sulfides as a replacement for antimony trisulfide in the formulation. The brake friction materials were developed in the form of standard brake pads as per the industrial practice. Thermal stability was measured for varying ingredients and developed brake pads using thermogravimetric analysis. The physical, mechanical and thermal properties of the developed brake pads were tested as per the industrial standards. The tribological properties were analyzed using the Chase test as per SAE J661. Worn surface analysis was done using a scanning electron microscope. Findings The experimental results indicate that the brake pads filled with premixed dual metal sulfides had good thermal stability, physical, chemical and mechanical properties with stable friction and less wear rate due to better lubrication preventing friction undulations. Originality/value This paper explains the influence of premixed dual metal sulfides as a replacement for antimony trisulfide in brake pads formulation to enhance the tribological performance by preventing friction undulations. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0144/


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2872
Author(s):  
Seyed Mohamad Reza Paran ◽  
Ghasem Naderi ◽  
Elnaz Movahedifar ◽  
Maryam Jouyandeh ◽  
Krzysztof Formela ◽  
...  

The effect of several concentrations of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the vulcanization and degradation kinetics of XNBR/epoxy compounds were evaluated using experimental and theoretical methods. The isothermal vulcanization kinetics were studied at various temperatures by rheometry and differential scanning calorimetry (DSC). The results obtained indicated that the nth order model could not accurately predict the curing performance. However, the autocatalytic approach can be used to estimate the vulcanization reaction mechanism of XNBR/epoxy/XHNTs nanocomposites. The kinetic parameters related to the degradation of XNBR/epoxy/XHNTs nanocomposites were also assessed using thermogravimetric analysis (TGA). TGA measurements suggested that the grafted nanotubes strongly enhanced the thermal stability of the nanocomposite.


2011 ◽  
Vol 1312 ◽  
Author(s):  
Ananta Raj Adhikari ◽  
Mircea Chipara ◽  
Karen Lozano

ABSTRACTThe effect of processing (shear) time on the mechanical behavior and thermal stability of multiwalled nanotube reinforced polyethylene was investigated. It was observed that the mechanical property (storage modulus, loss modulus) of the composites is process dependant whereas the thermal stability does not. The increase in mechanical behavior is attributed to a stronger interface between the nanotube and the polymer matrix.


2019 ◽  
Vol 972 ◽  
pp. 172-177
Author(s):  
Sirirat Wacharawichanant ◽  
Patteera Opasakornwong ◽  
Ratchadakorn Poohoi ◽  
Manop Phankokkruad

This work studied the effects of various types of cellulose fibers on the morphology, mechanical and thermal properties of poly(lactic acid) (PLA)/propylene-ethylene copolymer (PEC) (90/10 w/w) blends. The PLA/PEC blends before and after adding cellulose fibers were prepared by melt blending method in the internal mixer and molded by compression method. The morphological analysis observed that the presence of cellulose in PLA did not change the phase morphology of PLA, and PLA/cellulose composite surfaces were observed the cellulose fibers inserted in PLA matrix and fiber pull-out. The phase morphology of PLA/PEC blends was changed from brittle fracture to ductile fracture behavior and showed the phase separation between PLA and PEC phases. The presence of celluloses did not improve the compatibility between PLA and PEC phases. The tensile stress and strain curves found that the tensile stress of PLA was the highest value. The addition of all celluloses increased Young’s modulus of PLA. The PEC presence increased the tensile strain of PLA over two times when compared with neat PLA and PLA was toughened by PEC. The incorporation of cellulose fibers in PLA/PEC blends could improve Young’s modulus, tensile strength, and stress at break of the blends. The thermal stability showed that the degradation temperatures of all types of cellulose were less than the degradation temperatures of PLA. Thus, the incorporation of cellulose in PLA could not enhance the thermal stability of PLA composites and PLA/PEC composites. The degradation temperature of PEC was the highest value, but it could not improve the thermal stability of PLA. The incorporation of cellulose fibers had no effect on the melting temperature of the PLA blend and composites.


2020 ◽  
Vol 837 ◽  
pp. 174-180
Author(s):  
Sirirat Wacharawichanant ◽  
Attachai Sriwattana ◽  
Kulaya Yaisoon ◽  
Manop Phankokkruad

This work studied the morphology, mechanical and thermal properties of poly (lactic acid) (PLA)/ethylene-octene copolymer (EOC) (80/20) blends with different organoclay types. Herein, EOC was introduced to toughening PLA by melt blending and organoclay was used to improve compatibility and tensile properties of the blends. The two organoclay types were nanoclay surface modified with aminopropyltriethoxysilane 0.5-5 wt% and octadecylamine 15-35% (Clay-ASO) and nanoclay surface modified with dimethyl dialkyl (C14-C18) amine 35-45 wt% (Clay-DDA). The organoclay contents were 3, 5 and 7 phr. Scanning electron microscope (SEM) observation results revealed PLA/EOC blends demonstrated a two-phase separation of dispersed EOC phase and PLA matrix phase. The addition of organoclay significantly improved the compatibility between PLA and EOC phases due to EOC droplet size decreased dominantly in PLA matrix, so organoclay could act as an effective compatibilizer. The incorporation of organoclay increased significantly tensile strength of PLA/EOC/organoclay composites while Young’s modulus increased with 5 phr of organoclay. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-ASO in the blends could improve the thermal stability of the PLA/EOC blends.


2017 ◽  
Vol 32 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Bruno Ribeiro ◽  
LFP Santos ◽  
AL Santos ◽  
ML Costa ◽  
EC Botelho

Poly(ether-imide) (PEI)-based composites filled with multiwalled carbon nanotubes in a dispersed form (1.0 wt%) and as buckypaper (BP) (25 wt%) have been prepared by mixing solution and hot compression molding technique, respectively. Vacuum filtration technique with the aid of water-based surfactant Triton X-100 was employed to produce BP sheets. The thermal stability of the composites was evaluated by thermogravimetric analysis and revealed a strong increase in thermal degradation temperature when BPs were used as nanofiller. Ozawa–Wall–Flyn model was used to determine the kinetic parameters. It was observed an increase in activation energy as the nanotubes concentration rise, suggesting the formation of more thermally stable systems. In addition, half-life time as function of temperature demonstrated that BP-based composites could operate for 3200 years at 200°C. These results concluded that carbon nanotube BP could contribute to improve significantly the thermal stability of PEI matrix.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Abdulhadi A. Al-Juhani

Maleated polyethylene (MAPE) was used in this study as a model matrix for hosting hydrophobic nanoclay (C15A) and hydrophilic nanoclay (C30B), to investigate the effect of nanoclay loading on the bulk properties of the composites. Composites were prepared by melt-blending technique, with varying the loading from 0 to 9 wt.%. Tensile, oxidative TGA, and FE-SEM tests were employed for both C15A-filled polymer and C30B-filled polymer, which confirmed that C15A had better dispersion and was much superior to C30B for enhancing the mechanical properties and thermal stability of MAPE. Consequently, XRD and melt rheology tests were performed for C15A-filled polymer only. XRD confirmed the formation of nanocomposite structure, which could be the main reason for the significant increase in the thermal stability and viscosity. For example, compared to the neat polymer, the degradation temperature at the 20% mass loss was increased by 72°C after the addition of 5 wt.% C15A. Based on rheological analysis, the percolation threshold was around 3 wt.% loading of C15A. Fitting the viscosity data to the Cross model suggested that increasing C15A loading had a strong effect for increasing the shear thinning index and relaxation time of the nanocomposites.


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