A Comparative Study of the Structural, Optical, and Electrochemical Properties of Squarate-Based Coordination Frameworks

2013 ◽  
Vol 66 (4) ◽  
pp. 429 ◽  
Author(s):  
Pavel M. Usov ◽  
Tony D. Keene ◽  
Deanna M. D'Alessandro
Keyword(s):  
Thermal Expansion ◽  
Comparative Study ◽  
Electrochemical Properties ◽  
Near Infrared ◽  
Coefficient Of Thermal Expansion ◽  
Redox Properties ◽  
Electrochemical Measurements ◽  
Positive Coefficient ◽  
Trigonal Structure ◽  
Coordination Frameworks

Systematic studies of the thermal expansion, optical, and redox properties of a series of six squarate-based frameworks, [MII(C4O4)(H2O)2] (MII = MnII, FeII, CoII, NiII, ZnII, CdII) have revealed that five members of the series exhibit cubic structures in which the squarate ligands are configured in an ‘eclipsed’ phase, while the CdII analogue exhibits a trigonal structure with a ‘staggered’ orientation of the ligands. The ‘eclipsed’ structures are characterised by a positive coefficient of thermal expansion, while the CdII analogue exhibits zero thermal expansion. Ultraviolet-visible-near infrared (UV-Vis-NIR) spectra and electrochemical measurements indicate that electron delocalisation across the dianionic squarate bridge is absent.

Very high or close to zero thermal expansion by the variation of the Sr/Ba ratio in Ba1−xSrxZn2Si2O7 – solid solutions

2016 ◽  
Vol 45 (11) ◽  
pp. 4888-4895 ◽  
Author(s):  
Christian Thieme ◽  
Christian Rüssel
Keyword(s):  
Thermal Expansion ◽  
Solid Solutions ◽  
Coefficient Of Thermal Expansion ◽  
Positive Coefficient ◽  
Negative Coefficient ◽  
Very High

The compound BaZn2Si2O7 shows a highly positive coefficient of thermal expansion, while replacement of more than 10% of Ba2+ by Sr2+ results in a negative coefficient of thermal expansion.

scholarly journals A Comparative Study on the Characterization of Nanofibers with Cellulose I, I/II, and II Polymorphs from Wood

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 153 ◽  
Author(s):  
Haiying Wang ◽  
Suiyi Li ◽  
Tiantian Wu ◽  
Xiaoxuan Wang ◽  
Xudong Cheng ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Comparative Study ◽  
Coefficient Of Thermal Expansion ◽  
Cellulose Nanofibers ◽  
High Yield ◽  
Chemical Extraction ◽  
Cellulose Content ◽  
Cellulose I ◽  
Aspect Ratios

Polymorphic changes in cellulose nanofibers (CNFs) are closely related to their properties and applications, and it is of interest to investigate how polymorphic changes influence their properties. A comparative study on the properties of CNFs with cellulose I, I/II, and II polymorphs from wood was conducted herein. CNFs were obtained by chemical extraction combined with a simple and efficient mechanical treatment (one pass through a grinder). This process resulted in a relatively high yield of 80–85% after a simple grinding treatment. The polymorphic changes in the CNFs and the chemical composition, morphology, tensile performances, and thermal properties were systematically characterized and compared. The X-ray diffraction and FTIR analyses verified the existence of three types of purified pulps and CNFs with cellulose I, cellulose I/II, and cellulose II polymorphs (CNF-I, CNF-I/II, CNF-II). Morphological observations presented that these three types of CNFs all exhibited high aspect ratios and entangled structures. Tensile testing showed that the CNF films all exhibited high tensile strengths, and the fracture strains of the CNF-I/II (11.8%) and CNF-II (13.0%) films were noticeably increased compared to those of the CNF-I film (6.0%). If CNF-II is used as reinforcing material, its larger fracture strain can improve the mechanical performance of the CNF composites, such as fracture toughness and impact strength. In addition, CNF-I, CNF-I/II, and CNF-II films showed very low thermal expansion in the range 20–150 °C, with the coefficient of thermal expansion values of 9.4, 17.1, and 17.3 ppm/K, respectively. Thermogravimetric analysis (TGA) revealed that the degradation temperature of CNF-I and CNF-II was greater than that of CNF-I/II, which was likely due to increased α-cellulose content. This comparative study of the characterization of CNF-I, CNF-I/II, and CNF-II provides a theoretical basis for the application of CNFs with different polymorphs and could broaden the applications of CNFs.

NILO ALLOY 36

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Constant Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Iron Nickel

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..

UNISPAN LR35

Alloy Digest ◽  
1971 ◽  
Vol 20 (1) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Operational Level

Abstract UNISPAN LR35 offers the lowest coefficient of thermal expansion of any alloy now available. It is a low residual modification of UNISPAN 36 for fully achieving the demanding operational level of precision equipment. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and surface treatment. Filing Code: Fe-46. Producer or source: Cyclops Corporation.

DELTALLOY 4032

Alloy Digest ◽  
1998 ◽  
Vol 47 (4) ◽  
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Surface Finish ◽  
Coefficient Of Thermal Expansion ◽  
Single Point ◽  
High Strength ◽  
Corrosion And Wear

Abstract Deltalloy 4032 has good machinability and drilling characteristics when using single-point or multispindle screw machines and an excellent surface finish using polycrystalline or carbide tooling. The alloy demonstrates superior wear resistance and may eliminate the need for hard coat anodizing. Deltalloy 4032 is characterized by high strength and a low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion and wear resistance as well as machining and surface treatment. Filing Code: AL-347. Producer or source: ALCOA Wire, Rod & Bar Division.

RED X-20

Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Aluminum Silicon Alloy ◽  
Temperature Performance

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.

AA 4032

Alloy Digest ◽  
1990 ◽  
Vol 39 (7) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance

Abstract AA 4032 has a comparatively low coefficient of thermal expansion and good forgeability. The alloy takes on an attractive dark gray appearance when anodized which may be desirable in architectural applications. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-305. Producer or source: Various aluminum companies.

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