Electrical performance and reaction kinetics of silicone gels

1990 ◽  
Vol 5 (4) ◽  
pp. 795-800 ◽  
Author(s):  
C.P. Wong
Keyword(s):  
Reaction Kinetics ◽  
Integrated Circuit ◽  
High Performance ◽  
Large Scale ◽  
Protective Coatings ◽  
Electrical Performance ◽  
Scanning Calorimetry ◽  
Silicone Gels ◽  
Circuits Vlsi ◽  
Kinetics Of

Silicone gels are becoming more accepted as protective coatings for Very Large Scale Integrated circuits (VLSI) against severe environments due to their excellent electrical, thermal, and mechanical properties. Recent studies indicate that high performance silicone gels in low-cost, non-hermetic plastic packaging may replace conventional hermetic ceramic packaging. This paper describes the use of the soft silicone gels as coatings on Integrated Circuit (IC) devices, and the correlation between the material's cure temperature and cure time versus their adhesion and electrical reliability during 85°C, 85% RH and bias accelerating testing. In addition, the reaction kinetics of the silicone gel based on the Differential Scanning Calorimetry (DSC) study of the uncured sample will be reported.

REACTION KINETICS OF HEXAMETHYLENE DIISOCYANATE AND POLYPROPYLENE GLYCOLS

2014 ◽  
Vol 87 (4) ◽  
pp. 617-628
Author(s):  
Min-Tzung Ye ◽  
Shinn-Gwo Hong
Keyword(s):  
Reaction Kinetics ◽  
Frequency Factor ◽  
Mechanical Analysis ◽  
Hexamethylene Diisocyanate ◽  
Empirical Equations ◽  
Ozawa Method ◽  
Scanning Calorimetry ◽  
Isothermal Reaction ◽  
Molecular Weights ◽  
Kinetics Of

ABSTRACT The kinetics of the reaction between hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) of different molecular weights toward the synthesis of polyurethanes with versatile properties was studied using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). From the dynamic exotherms observed in DSC, it was found that the Kissinger equation modified by an additional temperature term in its frequency factor term was able to accurately describe the isothermal reaction kinetics of all HDI/PPG reactions. The modification can be justified by analyses with the Ozawa method and the modulus observed under DMA measurements. Regardless of the type of PPG used, the frequency factors changed with respect to the degree of conversion and maximized at near 70% conversion. The derivation of the modified kinetic equation is presented. In addition, the empirical equations describing the dependence of the activation energies and frequency factors on the molecular weights of PPG were also derived.

scholarly journals Curing Reaction Kinetics of the EHTPB-Based PBX Binder System and Its Mechanical Properties

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1266
Author(s):  
Xing Zhang ◽  
Yucun Liu ◽  
Tao Chai ◽  
Zhongliang Ma ◽  
Kanghui Jia
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Reaction Kinetics ◽  
Testing Machine ◽  
Curing Process ◽  
Binder System ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Curing Reaction ◽  
Kinetics Of

In this research, differential scanning calorimetry (DSC) was employed to compare the curing reaction kinetics of the epoxidized hydroxyl terminated polybutadiene-isophorone diisocyanate (EHTPB-IPDI) and hydroxyl terminated polybutadiene-isophorone diisocyanate (HTPB-IPDI) binder systems. Glass transition temperature (Tg) and mechanical properties of the EHTPB-IPDI and HTPB-IPDI binder systems were determined using the DSC method and a universal testing machine, respectively. For the EHTPB-IPDI binder system, the change of viscosity during the curing process in the presence of dibutyltin silicate (DBTDL) and tin 2-ethylhexanoate (TECH) catalysts was studied, and the activation energy was estimated. The results show that the activation energies (Ea) of the curing reaction of the EHTPB-IPDI and HTPB-IPDI binder systems are 53.8 and 59.1 kJ·mol−1, respectively. While their average initial curing temperatures of the two systems are 178.2 and 189.5 °C, respectively. The EHTPB-IPDI binder system exhibits a higher reactivity. Compared with the HTPB-IPDI binder system, the Tg of the EHTPB-IPDI binder system is increased by 5 °C. Its tensile strength and tear strength are increased by 12% and 17%, respectively, while its elongation at break is reduced by 10%. Epoxy groups and isocyanates react to form oxazolidinones, thereby improving the mechanical properties and thermal stability of polyurethane materials. These differences indicate that the EHTPB-IPDI binder system has better thermal stability and mechanical properties. During the EHTPB-IPDI binder system’s curing process, the DBTDL catalyst may ensure a higher viscosity growth rate, indicating a better catalytic effect, consistent with the prediction results obtained using the non-isothermal kinetic analysis method.

Passivating Organic Coatings with Silicone Gels: The Correlation Between the Material Cure & its Electrical Reliability

1989 ◽  
Vol 154 ◽  
Author(s):  
C. P. Wong
Keyword(s):  
Integrated Circuits ◽  
High Performance ◽  
Protective Coatings ◽  
Low Cost ◽  
Chip Surface ◽  
Surface Protection ◽  
Cure Time ◽  
Silicone Gels ◽  
Cure Temperature ◽  
Electrical Reliability

AbstractSilicone gels are becoming some of the most accepted protective coatings for VLSI integrated circuits due to their excellent electrical, thermal, and soft gel-like nature and properties, as well as their ultra-purity and ability to protect IC devices against severe environments. Recent studies indicate that proper IC Chip surface protection with high performance silicone gels in low-cost, non-hermetic plastic packaging might well replace the conventional hermetic ceramic packaging. This paper describes the use of the soft silicone gels and coatings in IC devices. It also describes the correlation between the material cure temperature and cure time versus their adhesion and electrical reliability during 85°C, 85% RH and bias accelerating testing.

Studies of the Physical Properties of Cycloaliphatic Epoxy Resin Reacted with Anhydride Curing Agents

2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Epoxy Resin ◽  
High Performance ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Low Viscosity ◽  
High Performance Polymer ◽  
Curing Agents ◽  
The Impact

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.

Thermal Reaction Kinetics of Fly Ash Cement Paste at the Age of 28 Days

2014 ◽  
Vol 668-669 ◽  
pp. 91-94 ◽  
Author(s):  
Xiao Fang He ◽  
Chang Wen Miao ◽  
Yong Hao Wu ◽  
Xin Xin Cao ◽  
Dan Liu
Keyword(s):  
Activation Energy ◽  
Fly Ash ◽  
Apparent Activation Energy ◽  
Reaction Kinetics ◽  
Thermal Reaction ◽  
Physical Parameters ◽  
Scanning Calorimetry ◽  
Kinetics Parameters ◽  
Cement Pastes ◽  
Kinetics Of

The thermal reaction kinetics of fly ash cement pastes were studied by Differential Scanning Calorimetry (DSC) and Thermal Gravity Analysis-Differential Thermal Gravity (TG-DTG) method, the kinetics parameters such as apparent activation energy was calculated by the Kissinger method, and the physical parameters were obtained. The result show that the fly ash cement pastes performance three endothermic reaction stages at different heating rates, peak temperatures of each stage at the range of 91.85~121.08°C, 453.93~496.48°C, and 680.21~751.62°C. TG-DTG show there were three thermal decomposition stages, thermal dehydration reaction apparent activation energy of fly ash cement pastes in each stage were 47.23kJ/mol, 128.84kJ/mol, and 134.07kJ/mol.

scholarly journals Synthesis of Benzene Tetracarboxamide Polyamine and Its Effect on Epoxy Resin Properties

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 782 ◽  
Author(s):  
Seoyoon Yu ◽  
Wonjoo Lee ◽  
Bongkuk Seo ◽  
Chung-Sun Lim
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
High Performance ◽  
Protective Coatings ◽  
Industrial Applications ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Adhesive Properties ◽  
Cross Sectional ◽  
Value Determination

Epoxy resins have found various industrial applications in high-performance thermosetting resins, high-performance composites, electronic-packaging materials, adhesives, protective coatings, etc., due to their outstanding performance, including high toughness, high-temperature performance, chemical and environmental resistance, versatile processability and adhesive properties. However, cured epoxy resins are very brittle, which limits their applications. In this work, we attempted to enhance the toughness of cured epoxy resins by introducing benzene tetracarboxamide polyamine (BTCP), synthesized from pyromellitic dianhydride (PMDA) and diamines in N-methyl-2-pyrrolidone (NMP) solvent. During this reaction, increased viscosity and formation of amic acid could be confirmed. The chemical reactions were monitored and evidenced using 1H-NMR spectroscopy, FT-IR spectroscopy, water gel-phase chromatography (GPC) analysis, amine value determination and acid value determination. We also studied the effect of additives on thermomechanical properties using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamical mechanical analysis (DMA), thermomechanical analysis (TMA) and by measuring mechanical properties. The BTCP-containing epoxy resin exhibited high mechanical strength and adhesion strength proportional to the amount of BTCP. Furthermore, field-emission scanning electron microscopy images were obtained for examining the cross-sectional morphology changes of the epoxy resin specimens with varying amounts of BTCP.

scholarly journals New experimental diagnostics in combustion of forest fuels: Microscale appreciation for a Macroscale approach

2018 ◽  
Author(s):  
Dominique Cancellieri ◽  
Valérie Leroy-Cancellieri ◽  
Xavier Silvani ◽  
Frédéric Morandini
Keyword(s):  
Thermal Degradation ◽  
Large Scale ◽  
Field Scale ◽  
Scanning Calorimetry ◽  
Natural Fire ◽  
Fire Propagation ◽  
New Device ◽  
Forest Fuels ◽  
Kinetics Of ◽  
Experimental Diagnostics

Abstract. In modelling the wildfire behaviour, a good knowledge of the mechanisms and the kinetic parameters controlling the thermal decomposition of forest fuel is of great importance. Lab-scale experimental diagnostics as Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Cone Calorimeter (CC) or Fire Propagation Apparatus (FPA) led to valuable results for modelling the thermal degradation of vegetal fuels and allowed several upgrades of pyrolysis models. But, these works remain beyond large-scale conditions of a wildland or forest fire. In an effort to elaborate the kinetic models under realistic natural fire conditions, a mass-loss device specifically designed for the field scale has been developed. The paper presents primary results gained using this new device, during large-scale experiments of controlled fires. The experimental data collected at the field scale lead to a new insight about thermal degradation processes of natural fuel, when compared to the kinetic laws established in TGA. These new results, provide a global description of the kinetics of degradation of Mediterranean forest fuels.

Rolling Processes and Performance of Cu-Fe In Situ Composites

2009 ◽  
Vol 79-82 ◽  
pp. 159-162
Author(s):  
Jun Qing Guo ◽  
He Yang ◽  
Ping Liu ◽  
Shu Guo Jia ◽  
Li Ming Bi ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Integrated Circuit ◽  
High Performance ◽  
Large Scale ◽  
Mechanical Performance ◽  
Sheet Material ◽  
Structural Function ◽  
In Situ Composites ◽  
In Situ Composite

The deformation processed Cu-based in-situ composite was a kind of structural function materials with high physical and mechanical performance and used widely in large scale integrated circuit. Especially, the sheet material of Cu-Fe in-situ composites was interested to researchers because the Fe was cheaper and the use of sheets was more widely in electron industry. In this study, the sheets of Cu-10Fe-1Ag in-situ composite were achieved by cold rolling which the thickness was from 6mm to 2.56mm, 1.28mm, 0.64mm and 0.32mm. Corresponding, the rolling ratio was 4.9, 5.3, 5.9 and 6.6. The maximum strength was 722Mpa at the rolling ratio 4.9. The conductivity was measured also with maximum 59.5% IACS. The experimental results show that the tensile strength and electrical resistance increase with the increasing of rolling strain. Although the conductivity of Cu-Fe in-situ composites was not very high, the matching of strength and conductivity was favorable. It is feasible that the high performance Cu-based in-situ composite can be obtained by cold rolling with merits of materials cheaper, melting simple and usage wide

scholarly journals A Low-Crossover and Fast-Kinetics Thiolate Negolyte for Aqueous Redox Flow Batteries

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Bin Yang ◽  
Zengyue Wang ◽  
Wanwan Wang ◽  
Yi-Chun Lu
Keyword(s):  
Reaction Kinetics ◽  
Large Scale ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
High Capacity ◽  
Fast Kinetics ◽  
Redox Flow Batteries ◽  
Crossover Rate ◽  
Flow Batteries ◽  
Kinetics Of

Aqueous redox flow batteries (ARFBs) are a promising technology for large-scale energy storage. Developing high-capacity and long-cycle negolyte materials is one of major challenges for practical ARFBs. Inorganic polysulfide is promising for ARFBs owing to its low cost and high solubility. However, it suffers from severe crossover resulting in low coulombic efficiency and limited lifespan. Organosulfides are more resistant to crossover than polysulfides owing to their bulky structures, but they suffer from slow reaction kinetics. Herein, we report a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. The thiolate denoted as 2-hydroxyethyl disulfide+potassium polysulfide (HEDS+K2S2) shows reduced crossover rate than K2S2, faster reaction kinetics than HEDS, and longer lifespan than both HEDS and K2S2. The 1.5 M HEDS+1.5 M K2S2 static cell demonstrated 96 Ah L-1negolyte over 100 and 200 cycles with a high coulombic efficiency of 99.2% and 99.6% at 15 and 25 mA cm-2, respectively. The 0.5 M HEDS+0.5 M K2S2 flow cell delivered a stable and high capacity of 30.7 Ah L-1negolyte over 400 cycles (691 h) at 20 mA cm-2. This study presents an effective strategy to enable low-crossover and fast-kinetics sulfur-based negolytes for advanced ARFBs.

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