Moisture absorption and hygroscopic swelling behavior of an underfill material

2012 ◽  
Vol 546 ◽  
pp. 143-152 ◽  
Author(s):  
Yi He
Keyword(s):  
Moisture Absorption ◽  
Swelling Behavior ◽  
Hygroscopic Swelling ◽  
Underfill Material

scholarly journals Numerical Simulation of Water Absorption and Swelling in Dehulled Barley Grains during Canned Porridge Cooking

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 230 ◽  
Author(s):  
Lei Wang ◽  
Mengting Wang ◽  
Mingming Guo ◽  
Xingqian Ye ◽  
Tian Ding ◽  
...  
Keyword(s):  
Moisture Absorption ◽  
Three Dimensional ◽  
Processing Conditions ◽  
Relative Deviation ◽  
Cooking Process ◽  
Proposed Model ◽  
Hygroscopic Swelling ◽  
3D Numerical Model ◽  
Barley Grains ◽  
Experimental Values

Understanding the hydration behavior of cereals during cooking is industrially important in order to optimize processing conditions. In this study, barley porridge was cooked in a sealed tin can at 100, 115, and 121 °C, respectively, and changes in water uptake and hygroscopic swelling in dehulled barley grains were measured during the cooking of canned porridge. In order to describe and better understand the hydration behaviors of barley grains during the cooking process, a three-dimensional (3D) numerical model was developed and validated. The proposed model was found to be adequate for representing the moisture absorption characteristics with a mean relative deviation modulus (P) ranging from 4.325% to 5.058%. The analysis of the 3D simulation of hygroscopic swelling was satisfactory for describing the expansion in the geometry of barley. Given that the model represented the experimental values adequately, it can be applied to the simulation and design of cooking processes of cereals grains, allowing for saving in both time and costs.

Hygroscopic Swelling Behavior of 3D Printed Parts due to Changes in Environmental Conditions

2016 ◽  
Author(s):  
Ju-young Park ◽  
Sangho Ha ◽  
Eunju Park ◽  
Daeil Kwon ◽  
Namhun Kim
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Room Temperature ◽  
Selective Laser Sintering ◽  
Swelling Behavior ◽  
Hygroscopic Swelling ◽  
Dimension Change ◽  
Nylon 12 ◽  
3D Printed ◽  
Local Weather

Selective laser sintering (SLS) printers have been used for rapid prototyping, and the prototypes of part assemblies have been reported to expand or shrink over time. This paper examines the hygroscopic swelling behavior of 3D printed parts from SLS printers. A total of 10 hexahedron samples were produced using nylon-12, which is a common material used for prototyping. Half of the samples were exposed to a high temperature to reduce the moisture content, and the rest were left at a room temperature. In the meantime, 13 dimensions of each sample were measured periodically along with the local weather records including relative humidity in order to track the hygroscopic swelling behavior of the samples. The results showed that the deformation was mostly occurred to the dimensions parallel to the sintering layers. Also, changes in these dimensions were found to have a high correlation with the relative humidity regardless of temperature conditions. These results imply that changes in environmental conditions such as relative humidity result in the deformation of 3D printed parts after production. The high correlation between dimension change and relative humidity also indicates the layup orientation is a decisive factor to predict the deformation of 3D printed parts. Thus, unexpected deformation of 3D printed parts can be avoided by optimizing the parts design considering the layup orientation and by controlling the environmental conditions.

In-situ characterization of moisture absorption and hygroscopic swelling of silicone/phosphor composite film and epoxy mold compound in LED packaging

2018 ◽  
Vol 84 ◽  
pp. 208-214 ◽  
Author(s):  
Ibrahim Khalilullah ◽  
Talukder Reza ◽  
Liangbiao Chen ◽  
Mark Placette ◽  
A.K.M. Monayem H. Mazumder ◽  
...  
Keyword(s):  
Composite Film ◽  
Moisture Absorption ◽  
In Situ Characterization ◽  
Hygroscopic Swelling

Thermal Degradation and Mass Transport of Underfill Material

2007 ◽  
Author(s):  
Wen-Hao Lee ◽  
D. S. Liang ◽  
W. P. Wang ◽  
C. S. Hsiao
Keyword(s):  
Thermal Degradation ◽  
Mass Transport ◽  
Adhesion Strength ◽  
Moisture Absorption ◽  
Plastic Material ◽  
Water Molecules ◽  
Packaging Materials ◽  
Weight Loss Curve ◽  
Solder Reflow ◽  
Underfill Material

In order to enhance the reliability of flip chip packages, the initiation and propagation of various interfacial failures and robust interfacial bonds between the underfill and the other components are highly desired. The water molecules inside the plastic material were chemically bonded with polymers by hydrogen bonds in the microholes formed by the polymer molecule chains. The bonding of water molecules and polymers reduced the adhesion strength at the interface between epoxy material and die. In this study, the interfacial bond strengths of commercial underfills with silicon nitride passivation are measured using bottom shear test. The thermal degradation of epoxy-based underfill material has been studied by thermogravimetric analysis (TGA). The results show that adhesion strength is correlated with TGA weight loss curve. Besides, epoxy is sensitive to moisture at high temperature storage. Moisture diffusion characterization at high temperatures in polymeric packaging materials is important since moisture absorption of polymeric packaging materials plays a determining role in “popcorn cracking” of IC packages during the solder reflow process especially for lead-free solder reflow profile. The moisture absorption was measured by using mass transport and diffusion theory.

scholarly journals Effects of humidity and phosphor on silicone/phosphor composite in white light-emitting diode package

2019 ◽  
Vol 30 (23) ◽  
pp. 20471-20478 ◽  
Author(s):  
Md Ashraful Hoque ◽  
Robert Kelley Bradley ◽  
Jiajie Fan ◽  
Xuejun Fan
Keyword(s):  
Thermal Expansion ◽  
White Light ◽  
Moisture Absorption ◽  
Coefficient Of Thermal Expansion ◽  
Light Emitting Diode ◽  
Moisture Sorption ◽  
Mechanical Stiffness ◽  
Light Emitting ◽  
Expansion Test ◽  
Hygroscopic Swelling

Abstract Silicone/phosphor composite, which serve as mechanical protection and light conversion material, is an integral part of white light-emitting diode (LED) package. In this paper, a comprehensive study is conducted to investigate the effect of humidity and phosphor on moisture absorption, hygroscopic swelling, mechanical behavior, as well as thermal properties of silicone/phosphor composite in comparison with the pure silicone. SEM/EDAX and FTIR were performed to identify the phosphor and silicone compositions. Through moisture sorption test, it has been observed that the addition of phosphor significantly lowers the capacity of moisture absorption, but accelerates the diffusivity of moisture absorption. The hygroscopic swelling test showed that the phosphor has little effect on the swelling compared to the pure silicone sample. Both moisture absorption/desorption and hygroscopic swelling/de-swelling are reversible. Strain ramp test revealed that the phosphor enhances the stiffness of the composite. The moisture absorption, however, has negligible impact on mechanical stiffness for both pure and composite samples. Finally, thermal expansion test showed that the coefficient of thermal expansion does not change with the addition of phosphor into pure silicone.

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