Octasilsesquioxane-reinforced DGEBA and TGDDM epoxy nanocomposites: Characterization of thermal, dielectric and morphological properties

“…The concept of cooperativity is related to the ease with which polymer chains move at T g . If the molecular chains in a polymer resist movement at T g , then the tan d peak will be broad [15]. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of the OGPOSS-containing hybrid materials.…”

Section: Thermal Propertiesmentioning

confidence: 99%

“…Several studies on POSS modified epoxy resins were reported in the last decades. Nagendiran et al [15] found that epoxy/POSS nanocomposites exhibited the higher glass transition temperature (T g ) values than the neat epoxy resin at lower concentrations of POSS (B3 wt%), which could be attributed to the nanoreinforcement effect and segmental level restriction of the motion by the addition of POSS in the polymer matrix; and they exhibited the lower T g values at higher loading of POSS ([3 wt%), which may be ascribed to the incomplete curing reaction of epoxy-amine and/or to the increase in free volume of the system. Lee and Lichtenhan [16] studied the thermal and viscoelastic properties of monofunctional POSS-reinforced EP, and the T g was observed to increase with the increasing POSS contents.…”

Section: Introductionmentioning

confidence: 99%

“…However, EP thermosets, like most polymers, lack thermal resistance and flame retardancy, particularly in certain applications where flame retardancy is a most required feature. The modification of EP via POSS could endow the materials improved thermal and oxidative resistance, flame retardancy, and dielectric properties [9][10][11][12][13][14][15]. Several studies on POSS modified epoxy resins were reported in the last decades.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and properties of epoxy resin/polyhedral oligomeric silsesquioxane hybrid materials

Zhang

Guan

2015

Polym. Bull.

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Epoxy resin (EP)/polyhedral oligomeric silsesquioxanes (POSS) hybrids were prepared based on diglycidyl ether of bisphenol-A and octapropylglycidylether POSS (OGPOSS). The morphology of EP/OGPOSS hybrids was characterized by scanning electron microscopy. Differential scanning calorimetry and dynamic mechanical analysis indicated that the glass transition temperature (T g ) of the hybrids decreased with the increase of OGPOSS content. This phenomenon was ascribed to the increased free volume with the addition of bulky OGPOSS. Additionally, thermogravimetric analysis indicated that all the epoxy hybrids displayed similar degradation profiles, suggesting that OGPOSS did not change the mechanism of EP. The incorporation of OGPOSS into EP matrix produced high char yields at high temperatures, suggesting improved flame retardancy. Microscale combustion colorimeter tests showed that incorporation of OGPOSS into epoxy thermosets could significantly improve the flame retardancy. The increasing OGPOSS content into EP matrix exhibited a decreasing trend in the values of dielectric constant compared with those of neat EP.

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“…12. Due to the better thermal stability of the TGDDM/DDS resin matrix [21], many obvious holes can be seen in the fractured surface as a result of thermal degradation of separated E-HBP molecular chains. From Fig.…”

Section: The Phase Structure After Cipsmentioning

confidence: 99%

The mechanical behaviors of epoxy-terminated hyperbranched polyester (E-HBP) as toughener in different epoxy resins

Xia

Yang

et al. 2018

Adv Compos Hybrid Mater

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Using epoxy-terminated hyperbranched polymer (E-HBP) to modify epoxy resin (EP) is an effective way to improve the toughness of EP. In the present study, two different epoxy resin systems with E-HBP are researched: a commercial diglycidyl ether bisphenol A (DGEBA) resin with anhydride as curing agent and a tetraglycidyl diaminodiphenyl methane (TGDDM) resin with diamine as curing agent. Characterization results show that the addition of E-HBP could improve the mechanical properties of the two epoxy resin systems, such as tensile strength, elongation, and modulus of elasticity. Meanwhile, the glass transition temperature (T g ) of the two systems does not decrease. However, the morphology of the tensile fracture surfaces of the two modified systems shows different behaviors. Significant plastic deformation could be observed in the fracture surfaces of the modified DGEBA/anhydride system, and particle cavitations are clearly shown in the fracture surfaces of the modified TGDDM/ diamine systems. The analysis of the tensile fracture surfaces suggests that firstly E-HBP participates in the curing process of the modified resin systems, followed by the chemical-induced phase separation; finally, a gradient transition interface layer (GTIL) is formed. Apart from these, during the external loading process, the mechanical behaviors (deformation or cavitation) of the separated E-HBP particles in the modified epoxy resins are affected by the properties of the epoxy matrix itself.

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Octasilsesquioxane-reinforced DGEBA and TGDDM epoxy nanocomposites: Characterization of thermal, dielectric and morphological properties

Cited by 97 publications

References 47 publications

Synthesis Improvement and Characterization of Polyhedral Oligomeric Octa(aminophenyl)silsesquioxane

Synthesis Improvement and Characterization of Polyhedral Oligomeric Octa(aminophenyl)silsesquioxane

Preparation and properties of epoxy resin/polyhedral oligomeric silsesquioxane hybrid materials

The mechanical behaviors of epoxy-terminated hyperbranched polyester (E-HBP) as toughener in different epoxy resins

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