scholarly journals An investigation of the effects of a silicalite type zeolite on PDMS-composites

2000 ◽  
Vol 65 (3) ◽  
pp. 173-179
Author(s):  
Borivoj Adnadjevic ◽  
Jelena Jovanovic
Keyword(s):  
Thermal Stability ◽  
Polymer Network ◽  
Equilibrium Degree ◽  
Degree Of Swelling ◽  
Type Zeolite ◽  
Time Required ◽  
Reinforcing Filler

The aim of this paper was to investigate the effect of a silicalite type zeolite on PDMS-zeolite composites. The obtained results show that the introduction of a silicalite type zeolite into polysiloxane matrices results in a change of the equilibrium degree of swelling of the composites in toluene, their hardness and their thermal stability. With increasing amount of zeolite, the time required to achieve the equilibrium degree of swelling (DSe) is reduced, the DSe decreases and the hardness increases. Two ranges of the effect of the zeolite concentration on the composite characteristics were noted. At zeolite concentrations up to about 12% there are significant changes of the DSe and the hardness with zeolite concentration, while these effects are considerably less pronounced at higher concentrations. The results obtained show that the silicalite type zeolite acts as a reinforcing filler. We believe that with increasing zeolite concentration in the composite the total number of established polymer-zeolite interactions increases, as does the spatial irregularity of the polymer network, but that the density of the interactions decreases. This could be the most probably explanation for the changes in the characteristics of the composite with changing zeolite concentration.

scholarly journals Hybrid Composite Laminates from UPE/ESOA Blend Reinforced with Chitosan and Bamboo Fiber: A Study of Mechanical and Thermal Properties

2020 ◽  
Vol 32 (6) ◽  
pp. 1321-1328
Author(s):  
Priyabrata Mohanty ◽  
Dibakar Behera ◽  
Shiv kumari Panda ◽  
Tapan Kumar Bastia ◽  
Prasanta Rath
Keyword(s):  
Composite Laminates ◽  
Unsaturated Polyester ◽  
Low Cost ◽  
Polymer Network ◽  
Filler Concentration ◽  
Mechanical And Thermal Properties ◽  
Thermosetting Polymers ◽  
Low Cost Housing ◽  
Enhanced Properties ◽  
Reinforcing Filler

The development of an inter-cross-linked polymer network of thermoset-thermoset blends have been extensively studied due to their enhanced mechanical properties. Among various polymer blends, modifications of unsaturated polyester (UPE) resin with epoxidized soybean oil acrylate (ESOA) combinations are an attractive route to promote the performance of the thermoset matrix and to overcome the inferior properties of both the components. Biodegradable and effectively accessible chitosan biodegradable waste material can shape the new stage for cutting-edge innovation items. Blend of both recyclable fibrous reinforcement and eco-friendly filler with two miscible thermosetting polymers will provide enhanced properties. At this time, chitosan up to 15 wt% (based on matrix weight) was utilized as reinforcing filler. At last, an interesting result was built up by confirming that chitosan filled chemically tailored bamboo and UPE/ESOA (80:20) biocomposites offered enhanced properties by 10 wt% of filler concentration with the most enhancements in whole properties. They have extensive variety of applications in the sector of low cost housing, structural projects and structural laminates.

Effect of Cenosphere on the Performance of Polyurethane/Polystyrene Interpenetrating Polymer Network Green Composites

2017 ◽  
pp. 158-185
Author(s):  
Roopa S. ◽  
Siddaramaiah
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Thermogravimetric Analysis ◽  
Castor Oil ◽  
Polymer Network ◽  
Thermal Characteristics ◽  
Mechanical Analysis ◽  
Interpenetrating Polymer Network ◽  
Toluene Diisocyanate ◽  
Green Composites

The effect of cenosphere content on the performances of polyurethane/polystyrene (PU/PS, 90/10) interpenetrating polymer network (IPN) based green composites have been studied. The PU/PS IPNs have been prepared using castor oil, toluene diisocyanate and styrene. IPN/cenosphere composites have been prepared with different weight fractions viz., 0, 5, 10, 20 and 30 wt % of cenosphere. The prepared IPN composites have been characterized by physico – mechanical, chemical and thermal behavior. The tensile strength of unfilled IPN was 1.79 MPa and a significant improvement in tensile strength (34%) was noticed for 10% cenosphere loaded IPN composite. The swelling behavior of the composites has been studied in different organic solvents. Thermal characteristics of the composites have been measured using differential scanning calorimeter, thermogravimetric analysis and dynamic mechanical analysis (DMA). A slight improvement in thermal stability was noticed for filler loaded specimens. Morphological features of cryo-fractured IPN/cenosphere green composites have been analyzed using SEM.

Estimation, from Swelling, of the Structural Contribution of Chemical Reactions to the Vulcanization of Natural Rubber. Part II. Estimation of Equilibrium Degree of Swelling

1964 ◽  
Vol 37 (2) ◽  
pp. 571-575 ◽  
Author(s):  
Bryan Ellis ◽  
G. N. Welding
Keyword(s):  
Natural Rubber ◽  
Chemical Reactions ◽  
Volume Fraction ◽  
Equilibrium Degree ◽  
Degree Of Swelling ◽  
Rubber Part ◽  
Structural Contribution

Abstract An investigation has been made of the measurement of degree of swelling of vulcanizates and the estimation of υτ, the volume fraction of polymer in a vulcanizate swollen to equilibrium. Methods have been established for dealing with a volatile swelling liquid, allowing for small percentages of nonpolymer in the vulcanizates, testing for diffusion equilibrium and correcting for swelling increment. The resulting values of υτ are suitable for use as described in the preceding Part I.

scholarly journals Mechanical, thermal and surface properties of polyacrylamide/dextran semi-interpenetrating network hydrogels tuned by the synthesis temperature

2013 ◽  
Vol 11 (2) ◽  
pp. 248-258 ◽  
Author(s):  
Maria Dinu ◽  
Maria Cazacu ◽  
Ecaterina Drăgan
Keyword(s):  
Thermal Stability ◽  
Polymer Network ◽  
Synthesis Temperature ◽  
Water Vapor Sorption ◽  
Interpenetrating Polymer Network ◽  
Vapor Sorption ◽  
Interpenetrating Network ◽  
Preparation Temperature ◽  
Thermal Stability Of ◽  
Network Morphology

AbstractThe mechanical, rheological, thermal, and surface behaviors of three polyacrylamide/dextran (PAAm/Dx) semi-interpenetrating polymer network (semi-IPN) hydrogels, prepared at 22°C, 5°C and −18°C, were investigated. The results were compared with those obtained on cross-linked PAAm without Dx synthesized under the same conditions. Hydrogels prepared at the lowest temperature were the most mechanically stable. The thermal stability of the semi-IPN hydrogels is slightly lower than the corresponding PAAm gels, irrespective of preparation temperature. The water vapor sorption capacity depended on the presence of Dx as well as preparation temperature, which determines the network morphology.

scholarly journals Rheological and thermal stability of interpenetrating polymer network hydrogel based on polyacrylamide/hydroxypropyl guar reinforced with graphene oxide for application in oil recovery

2021 ◽  
Vol 41 (9) ◽  
pp. 788-798
Author(s):  
Amir Narimani ◽  
Farid Kordnejad ◽  
Prabhjyot Kaur ◽  
Saeed Bazgir ◽  
Mahmood Hemmati ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Oil Recovery ◽  
Polymer Network ◽  
High Viscosity ◽  
Interpenetrating Polymer Network ◽  
Flow Activation Energy ◽  
Nanocomposite Hydrogels ◽  
Hydroxypropyl Guar ◽  
Hydrogel Matrix

Abstract The purpose of the present work is to enhance the thermal stability and rheological properties of semi-interpenetrating polymer network (IPN) hydrogel based on partially hydrolyzed polyacrylamide/hydroxypropyl guar (HPAM/HPG) nanocomposite reinforced with graphene oxide (GO), at temperatures (200 and 240 °F) for use in oil recovery applications. FTIR spectra of the IPN nanocomposite hydrogels revealed interactions of GO with HPAM/HPG chains. An increase in the viscosity is also observed from the rheological study. Moreover, IPN and its nanocomposite hydrogels exhibited non-Newtonian behavior. The decline of viscosity of IPN nanocomposite hydrogels was observed with an increase in the temperature from 200 to 240 °F but was still higher than IPN hydrogel without GO. Dispersion of GO through the HPAM/HPG hydrogel matrix was evaluated by SEM morphology and electrical conductivity. The IPN nanocomposite hydrogels showed high viscosity stability, thermal stability, and flow activation energy as compared to IPN hydrogel without GO. Therefore, the addition of 0.1 wt.% of GO to the HPAM/HPG matrix is suitable to create a cross-linked polymer solution with improved properties which may be beneficial for use in oil recovery applications.

Synthesis and Application of Electro-Thermally Sensitive Gels

2008 ◽  
Vol 61 ◽  
pp. 147-156 ◽  
Author(s):  
Karl Friedrich Arndt ◽  
Andreas Richter ◽  
Stephan Klatt ◽  
Georgi Paschew
Keyword(s):  
Phase Transition ◽  
Ph Value ◽  
Sensor Arrays ◽  
Molecular Transport ◽  
Ion Concentration ◽  
Volume Phase Transition ◽  
Equilibrium Degree ◽  
Volume Phase ◽  
Swelling Agent ◽  
Degree Of Swelling

Stimuli-sensitive change their volume (equilibrium degree of swelling), mechanical properties (elasticity, stiffness) and molecular transport properties in response to a small change in the properties of the swelling agent, like temperature, solvent composition, pH value, ion concentration, etc. Widespread used smart gels take advantages of the volume phase transition induced by a change of temperature. The temperature of volume phase transition depends on the interaction between gel and solvent. For a gel with defined chemical structure it can be changed by the composition of the swelling agent, e.g. content of salt or organic components. For application, e.g. in MEMS, an easy and controlled stimulation of volume phase transition is required. The degree of swelling (Q) and therefore the dimension of gel structures are determined by temperature. It is possible to regulate Q to a predetermined value by heating/cooling. Thermal energy inside a gel-based device can be easily generated and regulated by incorporated heating resistors and temperature sensors. Different structures (micro-spheres, pads, patterned layers) of smart hydrogels are applied. The switching between two different states of swelling is induced by changes of temperature or by changing the environment. Using the example of gel-based microvalves, sensors, sensor arrays, pumps, and chemostats (concentration control of chemical substances) the sensor-actuator properties and advantages of this group of polymers are discussed.

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