Highly transparent and flexible silica/cellulose films with a low coefficient of thermal expansion

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 52349-52356 ◽  
Author(s):  
Yuehan Wu ◽  
Xingzhong Zhang ◽  
Bin Li ◽  
Shilin Liu
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Cellulose Films ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Highly transparent and flexible silica/cellulose films with low thermal expansion coefficients have been prepared by the in situ synthesis of silica in cellulose scaffolds using Na2SiO3 as a precursor.

Preparation of solution-processable colorless polyamide-imides with extremely low thermal expansion coefficients through an in-situ silylation method for potential space optical applications

e-Polymers ◽  
2016 ◽  
Vol 16 (5) ◽  
pp. 395-402 ◽  
Author(s):  
Song Wang ◽  
Guangjie Yang ◽  
Shibin Wu ◽  
Ge Ren ◽  
Wei Yang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Linear Chain ◽  
Tensile Modulus ◽  
Optical Homogeneity ◽  
One Pot ◽  
System Architectures ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion

AbstractSeveral tough and flexible fluorinated polyamide-imide films were prepared from trimellitic anhydride chloride and 2,2′-bis(trifluoromethyl)benzidine through a facile one-pot in-situ silylation method. By incorporating fluorinated side groups, the solubility of the prepared polyamide-imide was greatly enhanced. Meanwhile, due to their linear chain configuration and the existence of hydrogen bonding, the prepared polyamide-imide films revealed high tensile strength, high tensile modulus, high glass transition temperature (Tg) and most interestingly, very low coefficient of thermal expansion (CTE) of 11 ppm/°C. Copolymerization with pyromellitic dianhydride (PMDA) led to an extremely low CTE of 4 ppm/°C which should be among the lowest values available for soluble polyamide-imides. The optical homogeneity and stress homogeneity of the obtained polyamide-imide films were also tested. After non-contact with substance and thermal treatment at 300°C, they revealed a better optical homogeneity and stress homogeneity than that of the commercially available Kapton polyimide (PI) films, with a PV value of 0.915 λ and RMS value of 0.163 λ. Thus, these colorless and soluble polyamide-imide films simultaneously possessing promising optical imaging performance are good candidates as novel diffractive membrane optical system architectures.

Thermal Expansion of SrZr4-xTix(PO4)6 Ceramics

2018 ◽  
Vol 281 ◽  
pp. 169-174
Author(s):  
Yang Wang ◽  
Yuan Yuan Song ◽  
Yuan Yuan Zhou ◽  
Lu Ping Yang ◽  
Fu Tian Liu
Keyword(s):  
Thermal Expansion ◽  
Relative Density ◽  
Thermophysical Properties ◽  
Sintering Temperature ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
High Relative Density ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Low thermal expansion ceramics have been widely applied in multiple fields. In this paper, a series of low thermal expansion ceramics SrZr4-xTix(PO4)6 was prepared and characterized. The SrZr4-xTix(PO4)6 ceramics could be well sintered in the temperature range of 1400~1500 °C. The effect of the addition of Ti substituting Zr and the sintering temperature was studied. The Ceramic with x =0.1 sintered at 1450 °C, the SrZr4-xTix(PO4)6 had a high relative density. The thermal expansion coefficients were about 3.301×10-6 °C-1. It was demonstrated that the microstructure of the SrZr4-xTix(PO4)6 could be altered by adding varying amount of Ti to tailor the thermophysical properties of the material.

Some recent developments in high-strength glasses and ceramics

1964 ◽  
Vol 282 (1388) ◽  
pp. 52-56
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Glass Ceramics ◽  
High Strength ◽  
Fine Grained ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Recent Developments ◽  
Expansion Coefficients ◽  
Mechanical Strengths

Two areas of development in the field of glasses and ceramics have produced new materials with unusual combinations of properties. Glass-ceramics are melted and formed as glasses by conventional glass-forming techniques, but by a subsequent heat treatment, they are converted to fine-grained crystalline structures with new and useful combinations of properties. Products with thermal expansion coefficients approaching zero and flexural strengths ranging from 10 000 to 50 000 Lb./in. 2 have been made though not all combinations of low thermal expansion coefficients and high mechanical strengths are possible. The second area of development is in so-called Chemcor glasses. Such glass products can be preferentially pre-stressed by chemical means so as to produce an outer layer with high compressive stress and a bending strength in the finished product up to 100 000 Lb/in. 2 .

Studies of Microdefects, Thermal Expansion and Magnetic Properties of Fe-Ni-Co Invar Alloys

2017 ◽  
Vol 373 ◽  
pp. 146-149
Author(s):  
Wen Deng ◽  
Li Xia Li ◽  
Shou Lei Xu ◽  
Wen Chun Zhang ◽  
Yu Yang Huang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Large Change ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Invar Alloys ◽  
Low Thermal Expansion ◽  
Expansion Coefficients ◽  
Fcc Phase ◽  
Bcc Phase

The microdefects, the thermal expansion coefficients and the magnetization -temperature curves of the Fe64Ni36-xCox (x=1~10) were characterized by means of positron lifetime, X-ray diffraction, Michelson's interferometer and VSM modular on PPMS, respectively. The Fe64Ni30Co6 alloy is a mixture of BCC and FCC structures. With the Co content increasing in Fe64Ni36-xCox alloys, the BCC phase increases, while the FCC phase decreases. In comparison with other Fe64Ni36-xCox alloys, the Fe64Ni31Co5 alloy has a rather high magnetization at temperature lower than Tc, a relatively large change of the magnetization with the temperature near Tc, and a rather low thermal expansion coefficient.

Nanoscale Chemical Mapping of Semiconductor Devices and Materials via PiFM

2018 ◽  
Author(s):  
Sung Park ◽  
Derek Nowak ◽  
Tom Albrecht
Keyword(s):  
Thermal Expansion ◽  
Self Assembly ◽  
Chemical Mapping ◽  
Force Microscopy ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Semiconductor Compounds ◽  
High Resolution Images ◽  
Expansion Coefficients ◽  
Microscopy Techniques

Abstract Nanoscale microscopy is an important technique in analyzing current semiconductor processes and devices. Many of the current microscopy techniques can render high resolution images of morphology and, in some cases, elemental information. However, techniques are still needed to give definitive nanoscale mapping of compound materials utilized in semiconductor processes such as Si3N4, SiO2, SiGe, and low-k materials. Photo-induced force microscopy (PiFM) combines IR spectroscopy with atomic force microscopy (AFM) to provide concurrent information on topography and chemical mapping. PiFM measures the attractive dipole-dipole photo-response between the tip and the sample and does not rely on repulsive force arising from absorption-based sample expansion. As such, PiFM works well with many of the inorganic semiconductor compounds (with low thermal expansion coefficients) as well as organic materials (with high thermal expansion coefficients) [1]. In this study, various examples of nanoscale chemical mapping of semiconductor samples (surfaces processed via directed self-assembly (DSA), strain in SiGe/SiO2 structure, photoresist, etc.) will be presented, all demonstrating ~ 10 nm spatial resolution

Thermal expansion and pore pressure generation in oil sands

1986 ◽  
Vol 23 (3) ◽  
pp. 327-333 ◽  
Author(s):  
J. G. Agar ◽  
N. R. Morgenstern ◽  
J. D. Scott
Keyword(s):  
Thermal Expansion ◽  
Pore Pressure ◽  
Oil Sands ◽  
Thermal Stresses ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Oil Sand ◽  
Thermal Expansion Coefficients ◽  
Stress Changes ◽  
Expansion Coefficients

The prediction of stress changes and deformations arising from ground heating requires the coupled solution of the heat transfer and consolidation equations. Heat consolidation as a class of problems is distinct from other thermally induced consolidation problems involving processes such as frost heave and thaw consolidation in that it involves heating to elevated temperatures well above normal ground temperatures. Two of the important parameters required in analyses of heat consolidation problems are thermal expansion coefficients and a coefficient of thermal pore pressure generation.Relationships describing thermal expansion behaviour and thermal pore pressure generation in oil sands are presented. Both drained and undrained thermal expansion coefficients for Athabasca oil sand were determined by means of heating experiments in the temperature range 20–300 °C. The thermal pore pressure generation coefficient was evaluated in undrained heating experiments under constant total confining stresses and under constant effective confining stresses. The equipment and experimental methods developed during this study are appropriate for determination of thermal expansion and pore pressure generation properties of oil sands and other unconsolidated geologic materials. Key words: thermal expansion, oil sand, tar sand, thermal pore pressure generation, heat consolidation, thermal consolidation, coefficient of thermal expansion, thermal stresses, ground heating, thermally enhanced oil recovery, thermoelasticity, undrained heating.

scholarly journals Epoxy molding compounds with low thermal expansion coefficients.

1989 ◽  
Vol 46 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Masatsugu OGATA ◽  
Hiroshi HOZOJI ◽  
Syunichi NUMATA ◽  
Noriyuki KINJO ◽  
Osamu HORIE
Keyword(s):  
Thermal Expansion ◽  
Molding Compounds ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Thermal expansion of troilite and pyrrhotite determined by in situ cooling (873 to 373 K) neutron powder diffraction measurements

2005 ◽  
Vol 69 (2) ◽  
pp. 205-216 ◽  
Author(s):  
C. Tenailleau ◽  
B. Etschmann ◽  
H. Wang ◽  
A. Pring ◽  
B. A. Grguric ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Powder Diffraction ◽  
Cation Vacancy ◽  
Neutron Powder Diffraction ◽  
Sulphide Minerals ◽  
Thermal Expansion Coefficients ◽  
Vacancy Ordering ◽  
The Mean ◽  
Expansion Coefficients

AbstractThe thermal expansion coefficients for natural troilite, FeS, Ni-rich pyrrhotite, Fe0.84Ni0.11S, and Ni-poor pyrrhotite, Fe0.87Ni0.02S, were measured during cooling by in situ neutron powder diffraction over the temperature range 873–373 K. Between 873 and 573 K, the mean thermal expansion coefficients for the three compositions are 7.4(3)×10−5 {FeS}, 8.0(4)×10−5 {Fe0.84Ni0.11S} and 8.5(4)×10−5 K−1 {Fe0.87Ni0.02S}. Below 573 down to 373 K, the first two increase considerably to 14.1(7)×10−5 {FeS} and 9.3(5)×10−5 {Fe0.84Ni0.11S} while the latter sample shows no significant variation, 8.4(5)×10−5 K−1. Below 573 K, the thermal expansion is highly anisotropic, with Δa/100 K−1 ranging from 0.89(9)% {FeS} to 0.48(12)% {Fe0.87Ni0.02S} while Δc/100 K−1 ranges from −0.39(11)% {FeS} to −0.13(2)% {Fe0.87Ni0.02S}.Upon cooling through 573 K, troilite and pyrrhotite undergo a transition where the FeS6 octahedra distort and in the case of pyrrhotite, cation-vacancy clustering occurs. The thermal expansion coefficients are bigger for low cation-vacancy concentrations and decrease as the pyrrhotites become less stoichiometric. This indicates that the thermal expansion in these minerals is damped by vacancy ordering or clustering. The thermal expansion coefficients for troilite and pyrrhotite are amongst the largest reported for sulphide minerals and their role in the formation of ore textures is discussed briefly.

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