Effect of the structure of silane-coupling agent on dynamic mechanical properties of dental resin-nanocomposites

2008 ◽  
Vol 110 (1) ◽  
pp. 507-516 ◽  
Author(s):  
Irini D. Sideridou ◽  
Maria M. Karabela
2015 ◽  
Vol 1767 ◽  
pp. 139-143
Author(s):  
Ramón Sánchez ◽  
Jacobo Aguilar ◽  
Silvia Y. Martínez ◽  
Reyes J. Sanjuan ◽  
Gerardo A. Mejía ◽  
...  

ABSTRACTDynamic mechanical properties of polypropylene (PP) and grafted polypropylene (PP-g-MA) composites reinforced with acetylated wheat straw fibers (WSF) is reported in this work. The materials were prepared with different fiber particle sizes (40, 80 and 140 U.S. mesh) and at different fiber contents (5, 10 and 15 wt.%). The PP and PP-g-MA composites, where anhydride maleic (MA) was used as coupling agent, were obtained using a twin-screw extruder; whereas an injection-molding machine molded the composite pellets into testing specimens. To observe the morphology of the composites, micrographs were taken with an optical microscope. The Dynamic mechanical properties were analyzed using a torsional rheometer. The morphological analysis showed a high porous structure somehow similar to foamed materials. The storage modulus (G′) increased by increasing the fiber content, and decreased with fiber particle sizes for the PP composites. Meanwhile, the use of the coupling agent additive promoted a modulus increase due to higher fiber-polymer interaction, from better adhesion and chemical bonds formation between the fibers-coupling agent-PP.


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.


2011 ◽  
Vol 675-677 ◽  
pp. 361-364 ◽  
Author(s):  
Yang Zhao ◽  
Jian Hui Qiu ◽  
Hui Xia Feng ◽  
Guo Hong Zhang ◽  
Liang Shao

Rice straw/Poly(butylene succinate)(PBS) composites were prepared by injection molding machine. The influence of content and particle size of rice straw on the mechanical properties of composites indicated that with the increase of rice straw content the tensile strength and fracture strain of the composites was decreased. With the same content of rice straw, the smaller particle size, the more obvious decreased. The influence of dosage of silane coupling agent(SCA) on the composites was studied, the result indicated that with the increase of SCA content, the interface of composite materials significantly improved, the Young’s modulus increased 362% after rice straw was treated by SCA. Thermal analysis showed that the adding of coupling agent didn’t undermine the thermodynamic stability of the composites.


2017 ◽  
Vol 25 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Jiuqiang Song ◽  
Yan Qin ◽  
Jia Chen ◽  
Siwen Qin

In this paper, a continuous glass fiber-reinforced polypropylene prepreg was prepared by fiber treatment with a silane coupling agent and MAH-g-PP resin. Continuous glass fiber-reinforced polypropylene sheets were made from prepreg and PP mats by hot-pressing; they displayed exceptional performance. This paper studies the effects of maleic anhydride grafting on the polypropylene crystallinity and MAH-g-PP content in the prepreg, and the mechanical properties of the composites. The results showed that modifying PP with maleic anhydride decreased the tacticity of the polypropylene molecular chain, which reduced the crystallinity and melting point. An excellent interface formed between the polypropylene and fiber after the glass fiber was treated with a silane coupling agent and MAH-g-PP resin. The mechanical properties of the polymer materials displayed more favorable properties as MAH-g-PP content increased; the ideal MAH-g-PP content was 50%.


2015 ◽  
Vol 30 (9) ◽  
pp. 1242-1254 ◽  
Author(s):  
Matheus Poletto ◽  
Ademir J Zattera

The mechanical and dynamic mechanical properties of cellulose fibers-reinforced polystyrene composites were investigated as a function of cellulose fiber content and coupling agent effect. The composites were prepared using a corotating twin-screw extruder and after injection molding. Three levels of filler loading (10, 20, and 30 wt%) and a fixed amount of coupling agent (2 wt%) were used. The results showed that a cellulose fiber loading of more than 20 wt% caused decrease in the mechanical properties. The addition of coupling agent substantially improves the mechanical and dynamic mechanical properties. The use of coupling agent improved the storage modulus and reduced the damping peak values of the composites due to the improved interfacial adhesion. The height of the damping peak was found to be dependent on the content of cellulose fiber and the interfacial adhesion between fiber and matrix. The adhesion factor values confirm that the better adhesion occurs when coupling agent is used.


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