Removable Polyurethane Encapsulants

1977 ◽  
Vol 9 (3) ◽  
pp. 299-311 ◽  
Author(s):  
K. B. Wischmann ◽  
G. L. Cessac ◽  
J. G. Curro
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Expansion ◽  
Reaction Rate ◽  
Coefficient Of Thermal Expansion ◽  
Thermoplastic Polyurethane ◽  
Electronics Packaging ◽  
Packaging Materials ◽  
Diffusion Controlled ◽  
Polar Organic Solvents

Two castable thermoplastic polyurethane formulations have been developed for use as removable electronics packaging materials. The first formulation would be employed in situations where some elastomeric properties are desired. Mechanical properties for this formulation are: tensile strength 1675 psi, elongation 480%, and modulus 2.2 X 104 psi. The second formulation more closely simulates an epoxy resin and the mechanical properties are: tensile strength 6040 psi, elongation 6.5%, and modulus 2.8 X 105 psi. Both casting resins can be filled (e.g., with Al2O3) which reduces the coefficient of thermal expansion (~ 80 X 10-6 to ~ 40 X 10-6/°C) and susceptibility to creep. The two formulations are soluble in polar organic solvents such as dimethylformamide and tetrahydrofuran. Both formulations were synthesized in bulk and based on reaction rate studies, they exhibit a diffusion controlled process in the latter stages of reaction.

Some Physical and Mechanical Properties of Pbo Fiber

1988 ◽  
Vol 134 ◽  
Author(s):  
J. Im ◽  
P.A. Percha ◽  
D.S. Yeakle
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Expansion ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Physical And Mechanical Properties ◽  
Gage Length ◽  
Dead Load ◽  
Fiber Tension ◽  
Pbo Fiber

ABSTRACTThe tensile properties of poly (paraphenylene benzobisoxazole) or PBO fiber strands were studied using two variables: gage length and the number of twists per inch. The gage length was varied from 1 to 10 inches with 2 twists of the fiber per inch. The effect of the number of twists per inch was studied by varying the number of twists from zero to 10 along a 5-inch gage length. The trends of tensile strength and modulus due to these variables were established and appropriate explanations of these behaviors are provided.The coefficient of thermal expansion (CTE) was studied on bare strands of PBO and Kevlar 49 (a product of Du Pont de Nemours & Co.) fibers, using a Du Pont 943 Thermomechanical Analyzer (TMA) equipped with a film and fiber tension assembly. The axial CTE of both fibers exhibited a dependence on the small dead load employed to keep the fibers straight. Kevlar 49 fiber, when wet, attained a much less negative value of CTE than when dry. In contrast, PBO fiber absorbed very little moisture, and the CTE remained unchanged.

Thermoplastic polyurethane/CNT nanocomposites with low electromagnetic resistance property

2021 ◽  
pp. 002199832110370
Author(s):  
Chia-Fang Lee ◽  
Chin-Wen Chen ◽  
Fu-Sheng Chuang ◽  
Syang-Peng Rwei
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermoplastic Polyurethane ◽  
Conductive Polymer ◽  
Resistance Coefficient ◽  
Equal Weight ◽  
Mechanical And Thermal Properties ◽  
Multi Wall Carbon Nanotubes ◽  
Twin Screw ◽  
Acrylic Ester

Multi-wall carbon nanotubes (MWCNTs) at 0.5 wt% to 2 wt% proportions were added to thermoplastic polyurethane (TPU) synthesized with polycarbonatediol (PCDL), 4,4’-methylene diphenyl diisocyanate (MDI), and 1,3-butanediol(1,3-BDO). To formulate a new TPU-MWCNT nanocomposite, the composite was melt-blended with a twin-screw extruder. To ensure the even dispersion of MWCNTs, dispersant (ethylene acrylic ester terpolymer; Lotader AX8900) of equal weight proportion to the added MWCNTs was also added during the blending process. Studies on the mechanical and thermal properties, and melt flow experiments and phase analysis of TPU-MWCNT nanocomposites, these nanocomposites exhibit higher tensile strength and elongation at break than neat TPU. TPU-MWCNT nanocomposites with higher MWCNT content possess higher glass-transition temperature (Tg), a lower melt index, and greater hardness. Relative to neat TPU, TPU-MWCNT nanocomposites exhibit favorable mechanical properties. By adding MWCNTs, the tensile strength of the nanocomposites increased from 7.59 MPa to 21.52 MPa, and Shore A hardness increased from 65 to 81. Additionally, TPU-MWCNT nanocomposites with MWCNTs had lower resistance coefficients; the resistance coefficient decreased from 4.97 × 1011 Ω/sq to 2.53 × 104 Ω/sq after adding MWCNTs, indicating a conductive polymer material. Finally, the internal structure of the TPU-MWCNT nanocomposites was examined under transmission electron microscopy. When 1.5 wt% or 2 wt% of MWCNTs and dispersant were added to TPU, the MWCNTs were evenly dispersed, with increased electrical conductivity and mechanical properties. The new material is applicable in the electronics industry as a conductive polymer with high stiffness.

Tensile properties of the FFF-processed thermoplastic polyurethane (TPU) elastomer

2021 ◽  
Author(s):  
Budi Arifvianto ◽  
Teguh Nur Iman ◽  
Benidiktus Tulung Prayoga ◽  
Rini Dharmastiti ◽  
Urip Agus Salim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Low Cost ◽  
Thermoplastic Polyurethane ◽  
High Strength ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Fused Filament Fabrication ◽  
Raster Angle ◽  
Manufacturing Techniques

Abstract Fused filament fabrication (FFF) has become one of the most popular, practical, and low-cost additive manufacturing techniques for fabricating geometrically-complex thermoplastic polyurethane (TPU) elastomer. However, there are still some uncertainties concerning the relationship between several operating parameters applied in this technique and the mechanical properties of the processed material. In this research, the influences of extruder temperature and raster orientation on the mechanical properties of the FFF-processed TPU elastomer were studied. A series of uniaxial tensile tests was carried out to determine tensile strength, strain, and elastic modulus of TPU elastomer that had been printed with various extruder temperatures, i.e., 190–230 °C, and raster angles, i.e., 0–90°. Thermal and chemical characterizations were also conducted to support the analysis in this research. The results obviously showed the ductile and elastic characteristics of the FFF-processed TPU, with specific tensile strength and strain that could reach up to 39 MPa and 600%, respectively. The failure mechanisms operating on the FFF-processed TPU and the result of stress analysis by using the developed Mohr’s circle are also discussed in this paper. In conclusion, the extrusion temperature of 200 °C and raster angle of 0° could be preferred to be applied in the FFF process to achieve high strength and ductile TPU elastomer.

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

scholarly journals Improving Mechanical, Thermal and Damping Properties of NiTi (Nitinol) Reinforced Aluminum Nanocomposites

2020 ◽  
Vol 4 (1) ◽  
pp. 19 ◽  
Author(s):  
Penchal Reddy Matli ◽  
Vyasaraj Manakari ◽  
Gururaj Parande ◽  
Manohar Reddy Mattli ◽  
Rana Abdul Shakoor ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Coefficient Of Thermal Expansion ◽  
Microwave Sintering ◽  
Hot Extrusion ◽  
Damping Capacity ◽  
Damping Properties ◽  
Niti Particle

In the present study, Ni50Ti50 (NiTi) particle reinforced aluminum nanocomposites were fabricated using microwave sintering and subsequently hot extrusion. The effect of NiTi (0, 0.5, 1.0, and 1.5 vol %) content on the microstructural, mechanical, thermal, and damping properties of the extruded Al-NiTi nanocomposites was studied. Compared to the unreinforced aluminum, hardness, ultimate compression/tensile strength and yield strength increased by 105%, 46%, 45%, and 41% while elongation and coefficient of thermal expansion (CTE) decreased by 49% and 22%, respectively. The fabricated Al-1.5 NiTi nanocomposite exhibited significantly higher damping capacity (3.23 × 10−4) and elastic modulus (78.48 ± 0.008 GPa) when compared to pure Al.

Plastic packaging materials of laminated composites made of polymer cover sheets and a nonwoven interlayer

2018 ◽  
Vol 22 (7) ◽  
pp. 2287-2301
Author(s):  
Mei-Chen Lin ◽  
Jia-Horng Lin ◽  
Jan-Yi Lin ◽  
Ting An Lin ◽  
Ching-Wen Lou
Keyword(s):  
Mechanical Properties ◽  
Laminated Composites ◽  
Thermoplastic Polyurethane ◽  
Soft Materials ◽  
Packaging Materials ◽  
Light Weight ◽  
Plastic Packaging ◽  
Crystal Stability ◽  
High Toughness ◽  
Sheet Extrusion

This study aims to improve the mechanical properties, stabilized structures, and light weight plastic packaging materials to realize diverse applications. A sheet extrusion machine is used to fabricate sandwich-structured composites, which are composed of two polymer cover sheets and a nonwoven interlayer. The samples are prepared in two batches with different cover sheets: thermoplastic polyurethane and polypropylene. Moreover, low-melting-point polyester (LMPET) fibers and Kevlar fibers are fabricated into a LMPET/Kevlar nonwoven interlayer. The laminated composites are evaluated in terms of morphologies, mechanical properties, combustion rates, and thermal behavior. Kevlar fibers are flame resistant and mechanically strong. LMPET fibers promote the interfacial bonding between layers. Thus, the laminated composites are good candidates as packaging materials, and they can be made with rigid or soft materials, depending on specified requirements. Rigid materials can provide higher strengths, and the distribution of fibers thus helps the PP-based laminated composites to obtain higher crystal stability. Moreover, using TPU with flexibility contributes to high extensibility, which grants the laminated composites with high toughness, light weight, and low restriction against the morphology. Such manufacturing is also efficient and economical, thereby satisfying the requirements of plastic packaging materials.

Determination of Mechanical Properties of Thin Film on Silicon Wafer

2003 ◽  
Author(s):  
Enboa Wu ◽  
Albert J. D. Yang ◽  
Ching-An Shao ◽  
C. S. Yen
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Silicon Wafer ◽  
Coefficient Of Thermal Expansion ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Bulk State

Nondestructive determination of Young’s modulus, coefficient of thermal expansion, Poisson ratio, and thickness of a thin film has long been a difficult but important issue as the film of micrometer order thick might behave differently from that in the bulk state. In this paper, we have successfully demonstrated the capability of determining all these four parameters at one time. This novel method includes use of the digital phase-shifting reflection moire´ (DPRM) technique to record the slope of wafer warpage under temperature drop condition. In the experiment, 1-um thick aluminum was sputtered on a 6-in silicon wafer. The convolution relationship between the measured data and the mechanical properties was constructed numerically using the conventional 3D finite element code. The genetic algorithm (GA) was adopted as the searching tool for search of the optimal mechanical properties of the film. It was found that the determined data for Young’s modulus (E), Coefficient of Thermal Expansion (CTE), Poisson ratio (ν), and thickness (h) of the 1.00 um thick aluminum film were 104.2Gpa, 38.0 ppm/°C, 0.38, and 0.98 um, respectively, whereas that in the bulk state were measured to be E=71.4 Gpa, CTE=23.0 ppm/°C, and ν=0.34. The significantly larger values on the Young’s modulus and the coefficient of thermal expansion determined by this method might be attributed to the smaller dislocation density due to the thin dimension and formation of the 5-nm layer of Al2O3 formed on top of the 1-um thick sputtered film. The Young’s Modulus and the Poisson ratio of this nano-scale Al2O3 film were then determined. Their values are consistent with the physical intuition of the microstructure.

scholarly journals The Use of Recycled Carpet in Low-Cost Composite Tooling Materials

Recycling ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 12 ◽  
Author(s):  
Kunal Mishra ◽  
Sarat Das ◽  
Ranji Vaidyanathan
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Low Cost ◽  
Value Engineering ◽  
Compressive Properties ◽  
Structural Composites ◽  
Environmental Deterioration ◽  
Composite Tooling

More than 250,000 metric tons (600 million pounds) of carpet are dumped in landfills every year. That creates a significant concern regarding environmental deterioration and economic liability. It is therefore imperative to develop sustainable post-consumer carpet-based products for high-value engineering applications such as composite tooling. To be considered as an acceptable composite tooling material, the composite needs to meet certain required properties such as a low coefficient of thermal expansion, excellent compressive properties, and high a hardness value after repeated exposure to curing cycles. The tooling composites must also exhibit the ability to endure several curing cycles, without deteriorating the mechanical properties. In the present investigation, post-consumer carpet has been recycled in the form of structural composites for tooling applications. The recycled carpet composites have been reinforced with 0.5 wt.% of graphene nanoplatelets to modify the material properties of the carpet composites. The results from compressive and hardness experiments demonstrate that the recycled carpet preserved its mechanical integrity even after several curing cycles. This indicates that recycled carpet composites have the potential to be a low-cost composite tooling alternative for the industry.

scholarly journals Hybrid Composites Based on Polypropylene with Basalt/Hazelnut Shell Fillers: The Influence of Temperature, Thermal Aging, and Water Absorption on Mechanical Properties

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 18 ◽  
Author(s):  
Anna Kufel ◽  
Stanisław Kuciel
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Water Absorption ◽  
Thermal Aging ◽  
Hybrid Composites ◽  
Coefficient Of Thermal Expansion ◽  
Tensile Modulus ◽  
Charpy Impact ◽  
Creep Tests ◽  
Influence Of Temperature

The aim of the research was to study the effects of adding natural fillers to a polypropylene (PP) matrix on mechanical and physical properties of hybrid composites. The 10%, 15%, and 20% by weight basalt fibers (BF) and ground hazelnut shells (HS) were added to the PP matrix. Composites were produced by making use of an injection molding method. Tensile strength, tensile modulus, strain at break, Charpy impact strength, and the coefficient of thermal expansion were determined. The influence of temperature, thermal aging, and water absorption on mechanical properties was also investigated. In addition, short-time creep tests were carried out. To characterize the morphology and the filler distribution within the matrix, a scanning electron microscope (SEM) was used. The results showed that the addition of the two types of filler enhanced mechanical properties. Furthermore, improvements in thermal stability were monitored. After water absorption, the changes in the tensile properties of the tested composites were moderate. However, thermal aging caused a decrease in tensile strength and tensile modulus.

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