Probing the Properties of Nanocomposites Synthesized from Aramid and Surface-Modified Clay

2009 ◽  
Vol 62 (5) ◽  
pp. 441 ◽  
Author(s):  
Sonia Zulfiqar ◽  
Zahoor Ahmad ◽  
Muhammad Ilyas Sarwar

Nanocomposites were prepared by the inclusion of layered silicates into the aramid matrix via a solution intercalation technique. Polyamide was synthesized by reacting 4,4′-oxydianiline with isophthaloyl chloride and then end-capping with carbonyl chloride end groups using excess diacid chloride. The compatibility between the two phases was obtained through surface modification of montmorillonite with long-chain alkyl diamine. The nanocomposites were characterized with regard to structural, morphological, mechanical, thermal, and water absorption measurements. These investigations confirmed the formation of delaminated and disordered intercalated nanostructures at different clay loadings. Mechanical properties were significantly enhanced relative to pristine polyamide, even with the addition of only 2 wt-% of nanoclay. Thermal decomposition temperatures of the nanocomposites were in the range 300–450°C. Glass transition temperature data exhibited improvement (123°C) up to 16 wt-% addition of organoclay. Water absorption of the neat aramid was rather high (5.7%), but decreased with augmenting clay content.

2008 ◽  
Vol 23 (12) ◽  
pp. 3330-3338 ◽  
Author(s):  
Sonia Zulfiqar ◽  
Muhammad Ilyas Sarwar

Oligomerically modified reactive montmorillonite clay was used in the preparation of aramid-layered silicate nanocomposites. The dispersion behavior of organoclay was monitored in the aramid matrix synthesized from 4-aminophenylsulfone and isophthaloyl chloride in dimethylacetamide. These polyamide chains were end-capped with carbonyl chloride groups to interact chemically with oligomerically modified layered silicate. Thin composite films containing 2 to 20 wt% of organoclay were probed for x-ray diffraction (XRD), transmission electron microscopy (TEM), mechanical testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water absorption measurements. XRD and TEM results described the distribution level of clay platelets and morphology of hybrid materials. Mechanical measurements revealed that modulus and strength improved up to 6 wt% clay loading, while toughness of nanocomposites increased with the addition of 2 wt% clay content in the matrix. The elongation showed a decreasing trend with increasing clay content in the hybrids. Thermal-decomposition temperatures of the nanocomposites were in the range 225 to 450 °C. The glass-transition temperature increased up to 12 wt% addition of organoclay in the matrix relative to pristine aramid depicting interfacial interactions among the phases. Water absorption of the nanocomposites reduced with augmenting organoclay loading, indicating decreased permeability.


2012 ◽  
Vol 455-456 ◽  
pp. 650-654 ◽  
Author(s):  
He Yi Ge ◽  
Jian Ye Liu ◽  
Xian Qin Hou ◽  
Dong Zhi Wang

The physical and mechanical properties of nanometer ZrO2-ZrO2fiber composite ceramics were studied by introduction of ZrO2fiber. ZrO2composite ceramics at different sintering temperature was investigated by porosity and water absorption measurements, flexual strength and thermal shock resistance analysis. Results showed that ZrO2composite ceramics containing 15 wt% ZrO2fiber with sintering temperature of 1650°C exhibited good mechanical properties and thermal shock resistance. The porosity and the water absorption were 8.84% and 1.62%, respectively. The flexual strength was 975 MPa and the thermal shock times reached 31 times. Scanning electron microscope (SEM) was used to analyze the microstructure of ZrO2composite ceramics.


2014 ◽  
Vol 1052 ◽  
pp. 242-248
Author(s):  
Hong Kai Zhao ◽  
Hong Li Wang

Through the polymerization and grafting reaction of bisphenol A dianhydride and bisphenol A diamine, the polyimide activator (PI activator) of acyl caprolactam end capping is obtained and then the anionic in-situ polymerization modified nylon 6 resin is obtained. Viscosity analysis shows that PI consumption is higher than 0.1 (of monomer mass), the reaction temperature is higher than 160°C, the viscosity rises rapidly in a short time and the rapid polymerization molding can be realized; when PI consumption is higher than 0.15 (of monomer mass), the water absorption of matrix resin will be lower than 1.4%; compared with the nylon resin, its water absorption is significantly lowered and its mechanical property is improved greatly; microscopic analysis shows that PI molecules fail to enter the crystalline phase of the nylon 6 and form lamellar crystals in the nylon matrix, which plays a role of enhancement and obstruction; differential thermal analysis shows that PI reduces the melting enthalpy and melting point temperature of nylon 6 resin, which indicates that PI reduces the crystallization capacity of nylon 6.


2011 ◽  
Vol 306-307 ◽  
pp. 754-757 ◽  
Author(s):  
Xian Qin Hou ◽  
Jian Ye Liu ◽  
He Yi Ge

The physical and mechanical properties of alumina (Al2O3) ceramics by introduction of zirconia (ZrO2) fiber were studied. ZrO2/Al2O3ceramics at different sintering temperature was investigated by porosity and water absorption measurements, flexual strength and thermal shock resistance analysis. Results showed that Al2O3 ceramics containing 15 wt% ZrO2fiber with sintering temperature of 1650°C exhibited good mechanical properties and thermal shock resistance. The porosity and water absorption were 7.4% and 0.69%, respectively. The flexual strength was 613 MPa and the thermal shock times reached 29 times. Scanning electron microscope (SEM) was used to analyze the microstructure of Al2O3 ceramics.


2002 ◽  
Vol 712 ◽  
Author(s):  
Antonia Moropoulou ◽  
Asterios Bakolas ◽  
Petros Moundoulas ◽  
Eleni Aggelakopoulou ◽  
Sofia Anagnostopoulou

ABSTRACTCement based mortars used for historic masonry restoration presented unsatisfactory results, due to their chemical and physico-mechanical incompatibility to original buildings. In the present research, several syntheses of restoration mortars are produced using traditional techniques and materials such as binders (aerial and natural hydraulic lime), pozzolanicadditives (natural and artificial pozzolanas) and aggregates (sand and crushed brick). The technical characteristics of the mortars were determined using mechanical tests (compressive and flexural) and mercury intrusion porosimetry measurements at the time of 1, 3, 9, 15 months of curing. Water absorption measurements were performed at the time of 9 and 15 months curing, in order to evaluate mortars microstructural characteristics, their rate of water absorption and the total percentage of absorbed water. The aerial lime - artificial pozzolana mortar presented the best mechanical and microstructural performance. Hydraulic mortars acquired the maximum of the mechanical strength in 1 month, lime - pozzolana mortars in 3 months while aerial lime mortars continue to gain mechanical strength even in 15 months curing. Furthermore, the use of ceramic aggregates produces lightweight and elastic mortars, compatible to historicones.


2012 ◽  
Vol 488-489 ◽  
pp. 82-86 ◽  
Author(s):  
Sirirat Wacharawichanant ◽  
Paramaporn Sahapaibounkit ◽  
Unchana Saeueng

This work investigated the effect of montmorillonite clay surface modified with 25-30 wt% trimethyl stearyl ammonium (clay) on mechanical, thermal and morphological properties of polyoxymethylene (POM)/clay nanocomposites were investigated. The results showed that POM/clay nanocomposites could maintain or decrease their tensile strength for a certain clay loading range. The Young’s modulus of the nanocomposites increased by adding clay in a range of 0.5-4 wt% while the impact strength showed an increase in a range of 0.5-2 wt%. The percent strain at break of the nanocomposites decreased with increasing filler content. The thermal degradation temperature decreased with an increase of clay content thus the addition of clay did not improve the thermal stability of POM. The microstructure of neat POM and POM/clay nanocomposites was observed that the dispersion of clay was a good in POM matrix at low clay content. The nanocomposites formed the intercalated structure with clay, and the intercalated clay stacks were distributed uniformly in the nanocomposite. The increase of clay content observed increasing of brittleness in POM/clay nanocomposites.


2015 ◽  
Vol 17 (7) ◽  
pp. 3737-3739 ◽  
Author(s):  
Saikat Dutta ◽  
Linglin Wu ◽  
Mark Mascal

Biomass-derived CMF is oxidized to the acid chloride CMFCC in a single step using inexpensive t-butyl hypochlorite. Likewise, DFF, also a CMF derivative, is oxidized directly to the diacid chloride FDCC. The products are platforms for a variety of chemical derivatives of carbohydrates.


Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 227-237 ◽  
Author(s):  
R. E. A. Midtbø ◽  
J. M. Rykkje ◽  
M. Ramm

AbstractThe Tarbert Formation on a north±south oriented structure along the eastern flank of the Viking Graben has been studied. The reservoir in the two wells studied is buried ~100 m deeper in the northern than in the southern well. The present reservoir temperature is ~130°C. The reservoir quality is good, but due to extensive illitization of kaolin, the northern well shows lower permeability values than the southern well, for similar porosity values. The initial composition of the analysed samples in the two wells is very similar. There are no significant differences in total clay content and both wells contain K-feldspars and kaolin. However, the diagenetic alteration is more advanced in the deeper well. Total porosity is about the same in both wells but, due to illitization, the ratio of micro- vs. macro-porosity is higher in the deeper well. Petroleum emplacement in the structure occurred in two phases: oil emplacement predates, whereas gas emplacement postdates, most of the quartz cementation. In the deeper well, illitization occurred after gas emplacement.


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