scholarly journals Effects of Kaolin Surface Treatments on the Thermomechanical Properties and on the Degradation of Polypropylene

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Melia Guessoum ◽  
Sorya Nekkaa ◽  
Françoise Fenouillot-Rimlinger ◽  
Nacerddine Haddaoui

The effects of kaolin content and treatments on the thermal and mechanical properties and on the degradation of polypropylene were examined using mechanical tests, differential scanning calorimetry (DSC), and thermogravimetry (TGA). The weak interactions filler/matrix have been reinforced using a modification with urea then with an ammonium salt and a surface treatment with a silane coupling agent. The XRD results showed that the peak at thed-value of 10.7 Å increases in urea/kaolin complex, but the treatment with the ammonium salt caused the return to the initial state of the clay. FTIR results showed the appearance of new bands characteristic of the interactions between urea and kaolinite and the alkylammonium and kaolinite. The mechanical properties of the composites exhibited important variations while the DSC results showed the decrease of the crystallization temperature as a function of kaolin content. TGA thermograms pointed out the improvement of the composites' thermal stability.

2013 ◽  
Vol 844 ◽  
pp. 77-80
Author(s):  
Warisada Sila-On ◽  
Jatuporn Pratoomted ◽  
Utsana Puapermpoonsiri ◽  
Chaiwute Vudjung ◽  
Wiwat Pichayakorn

Novel hydrogels based on natural rubber latex (NRL) and rice starch (RSt) (1:2 ratio) were prepared with various amount of N,N-methylenebisacrylamide (MBA) and 2.5 phr of maleic acid to form interpenetrating networks (IPN) using free-radical polymerization technique. The thermal and mechanical properties were performed by differential scanning calorimetry and mechanical tests. From data obtained, the change in Tg of rubber and melting point of RSt indicated that polymer-polymer interaction could be formed in IPN hydrogel. The higher amount addition of MBA created more mechanical strength of IPN hydrogels caused by the higher of interlacement formation. However, their mechanical strength of such hydrogels was lower than that of NRL alone due to the formation of amorphous structure in IPN hydrogel. These IPN hydrogels also improved the swelling property which will be utilized for wound healing application.


2021 ◽  
Vol 11 (13) ◽  
pp. 6218
Author(s):  
Balázs Ádám ◽  
Zoltán Weltsch

Polylactic acid (PLA) is one of the most promising biopolymers often used as a raw material in 3D printing in many industrial areas. It has good mechanical properties, is characterized by high strength and stiffness, but unfortunately, it has some disadvantages; one is brittleness, and the other is slow crystallization. Amounts of 1–5% SEBS (styrene-ethylene-butylene-styrene) thermoplastic elastomer were blended into the PLA and the thermal and mechanical properties were investigated. DSC (Differential Scanning Calorimetry) measurements on the filaments have shown that SEBS increases the initial temperature of crystallization, thereby acting as a nucleating agent. The cooling rate of 3D printing, on the other hand, is too fast for PLA, so printed specimens behave almost amorphously. The presence of SEBS increases the impact strength, neck formation appears during the tensile test, and in the bending test, the mixture either suffers partial fracture or only bends without fracture. Samples containing 1% SEBS were selected for further analysis, mixed with 0.06 and 0.1% carbon nanotubes (CNTs), and tested for thermal and mechanical properties. As a result of CNTs, another peak appeared on the DSC curve in addition to the original single-peak crystallization, and the specimens previously completely broken in the mechanical tests suffered partial fractures, and the partially fractured pieces almost completely regained their original shape at the end of the test.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1662
Author(s):  
Dongyuan Du ◽  
Yujing Tang ◽  
Lu Yang ◽  
Chao Tang

In order to study the influences of amino silane coupling agents with different grafting densities on the surface of nano silica on the thermomechanical properties of cross-linked epoxy resin, the molecular dynamics method was used to establish an amorphous model and calculate the mechanical properties, glass transition temperature, mean square displacement, hydrogen bond, binding energy, and radial distribution function of the composite models in this paper. The results are as follows: with the increase of the grafting density of an amino silane coupling agent on the surface of nano silica particles, the mechanical properties and glass transition temperature of epoxy resin showed a trend of increasing first and then decreasing. When the grafting ratio was 9%, the mechanical properties and glass transition temperature of the epoxy resin were the largest, and the glass transition temperature was increased by 41 K. At the same time, it was found that the higher the grafting ratio, the lower the chain movement ability, but the higher the binding energy. Besides, the binding energy between the nanoparticles of the grafted silane coupling agent and epoxy resin was negatively correlated with the temperature. By analyzing the hydrogen bond and radial distribution function, the results showed that the improvement of the grafted silane coupling agent on the surface of the nanoparticle to the thermomechanical properties of the epoxy resin was related to the OH···O and NH···O hydrogen bonds. The analysis results indicated that the proper grafting density should be selected based on the established model size, selected nanoparticle diameter, and epoxy resin materials in order to better improve the thermomechanical properties of the epoxy resin.


2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Morteza Hajian ◽  
Gholam Ali Koohmareh ◽  
Afsaneh Mostaghasi

The effects of titanate as a coupling agent and some particulate nanoscale particles such as TiO2, CaCO3, and ZnO on thermal and mechanical properties of emulsion polyvinylchloride (E-PVC) were investigated by thermogravimetric analysis (TGA), and mechanical tests. In this research, it was found that, in the presence of nanoparticles of CaCO3, TiO2, and ZnO, the peak temperature of dehydrochlorination of E-PVC was shifted to higher temperatures, and the rate of mass loss was decreased. Also results of differential scanning calorimetry showed that the addition of nanoparticle of CaCO3, TiO2, and ZnO led to an increase in glass transition temperature. The impact strength, elastic modulus and toughness of the samples were enhanced after addition of 0–10 part of filer in hundred parts of resin (phr) nano-CaCO3, nano-TiO2, and nano-ZnO due to improvement of compatibility of the polymer and the nano-particles. Also UV and thermal stability of the samples were enhanced by means of the nanoparticles. It was found that, in the presence of titanate as coupling agent, content of additives that could be used in the composite of PVC shifts to higher amounts.


2021 ◽  
Vol 891 ◽  
pp. 150-163
Author(s):  
Jorge Mauricio Fuentes ◽  
Omar Flor Unda ◽  
Santiago Ferrandiz ◽  
Franyelit Suarez

In this article presents evidence about performance of mechanical properties of polycarbonate and nylon materials, which are used in the additive manufacturing by deposition of molten material and that have been subjected to sterilization processes by moist heat at 121°C and dry heat at 140°C. This study provides useful information to consider the use of these materials in sanitary and sterile settings. Mechanical tests of tensile, flex, hardness, Izod impact, thermal tests in Differential Scanning Calorimetry DSC, Thermomechanical analysis TMA and Scanning Electron Microscopy SEM were performed. It is concluded that the mechanical and thermal properties have not been altered through the effect of temperature in sterilization processes.


2019 ◽  
Vol 33 (10) ◽  
pp. 1383-1395
Author(s):  
Hongjuan Zheng ◽  
Zhengqian Sun ◽  
Hongjuan Zhang

Poly(lactic acid) (PLA) has good environmental compatibility, however, its high brittleness, slow rate of crystallization, and low heat distortion temperature restrict its widespread use. To overcome these limitations, in this study, PLA was mixed with walnut shell (WS) powders. The effects of WS powders on the morphology and the thermal and mechanical properties of PLA were investigated. The products were characterized by differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarizing optical microscopy (POM), and various mechanical property testing techniques. The results showed that WS powders had a significant effect on the morphology and the thermal and mechanical properties of PLA. The tensile strength, impact strength, and elongation at break of the PLA/WS composites first increased and then decreased with the increasing addition of WS powders. When the addition of WS powders was about 0.5 wt%, they reached maximum values of 51.2 MPa, 23.3 MPa, and 19.0%, respectively. Compared with neat PLA, the spherulite grain size of the composites could be reduced and many irregular polygons were formed during crystallization. The melting, cold crystallization, and glass-transition temperatures of the composites were lower than those of neat PLA.


2012 ◽  
Vol 268-270 ◽  
pp. 127-133
Author(s):  
Chen Zheng ◽  
Yan Yan Xu ◽  
Takahiko Kawai ◽  
Shin-ichi Kuroda

In order to improve the properties and the processability of kenaf fiber (KF) / polystyrene (PS) composites, the newly synthesized polymeric silane coupling agent (CA) was utilized and evaluated. KFs were reacted with CA in the melt system and in the solvent system. The composites reinforced by the modified KF showed enhanced mechanical properties compared with those reinforced by the unmodified KF. The effect was especially remarkable when the KF was modified with CA in the solvent system. As the CA content increases, the surface of KF recovered from the composites showed the higher Si / C ratio indicating the good reaction between KF and CA. The modified composites also showed a remarkable reduction in water uptake rate.


2016 ◽  
Vol 36 (8) ◽  
pp. 853-860 ◽  
Author(s):  
Vahabodin Goodarzi ◽  
Zahed Ahmadi ◽  
Mohammad Reza Saeb ◽  
Farkhondeh Hemmati ◽  
Mehdi Ghaffari ◽  
...  

Abstract Since polyethylene (PE) has been widely accepted for the production of high-pressure fluid conveying pipelines, studies devoted to weldability of PE connections were always of major importance. In this study, two industrial PE grades designed for pipe production, namely PE80 and PE100, were injection molded, cut, and then welded as PE100-PE100, PE100-PE80, and PE80-PE80. The heat-welded joints were assessed by differential scanning calorimetry and tensile measurements. The results obtained from thermal and mechanical analyses were compared with equivalents for aged samples. Thermal analysis revealed that the melting point of the PE100-PE100 sample is obviously larger than the one for the PE80-PE80 joint, for the PE80 chains deteriorate the crystallization of PE100. Further, the PE80-PE80 sample showed the lowest lamellar thickness and crystalline molecular weight among the studied joints. The aging process was found to increase lamellar thickness and molecular weight, though in the PE100-PE100 sample such quantities very limitedly increased. The yield stress of aged joints was higher than that for just-prepared samples, while an inverse trend was seen for strain at break. From a practical viewpoint, the PE100-PE100 welds offer better properties.


Sign in / Sign up

Export Citation Format

Share Document