scholarly journals Correlation of the Abbe Number, the Refractive Index, and Glass Transition Temperature to the Degree of Polymerization of Norbornane in Polycarbonate Polymers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2484 ◽  
Author(s):  
Noriyuki Kato ◽  
Shinya Ikeda ◽  
Manabu Hirakawa ◽  
Hiroshi Ito
Keyword(s):  
Refractive Index ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Degree Of Polymerization ◽  
Glass Transition Temperatures ◽  
Unique Reaction ◽  
Transparent Polymers ◽  
End Group ◽  
Low Refractive Index

The influences of the average degree of polymerization (Dp), which is derived from Mn and terminal end group, on optical and thermal properties of various refractive indexed transparent polymers were investigated. In this study, we selected the alicyclic compound, Dinorbornane dimethanol (DNDM) homo polymer, because it has been used as a representative monomer in low refractive index polymers for its unique properties. DNDM monomer has a stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxy end group and phenolic end group polymers, the refractive index (nd) decreased with increasing Dp, and both converged to same value in the high Dp region. However, the Abbe number (νd) of a hydroxy end group polymer is not dependent on Dp, and the νd of a phenolic end group polymer is greatly dependent on Dp. As for glass transition temperatures (Tg), both end group series were increased as Dp increased, and both converged to the same value.

Well-defined high refractive index poly(monothiocarbonate) with tunable Abbe's numbers and glass-transition temperatures via terpolymerization

2015 ◽  
Vol 6 (27) ◽  
pp. 4978-4983 ◽  
Author(s):  
Ming Luo ◽  
Xing-Hong Zhang ◽  
Bin-Yang Du ◽  
Qi Wang ◽  
Zhi-Qiang Fan
Keyword(s):  
Refractive Index ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Propylene Oxide ◽  
High Refractive Index ◽  
Transition Temperatures ◽  
Cyclohexene Oxide ◽  
Glass Transition Temperatures

Poly(monothiocarbonate) with tunable Abbe's number and glass-transition temperature is synthesized via terpolymerization of COS with propylene oxide and cyclohexene oxide.

A Copolymerization Modified Acrylate Resin and its Polyhedral Oligomeric Silsesquioxane Composites

2014 ◽  
Vol 887-888 ◽  
pp. 97-100
Author(s):  
Xiao Lan Hu ◽  
Xi Lan ◽  
Teng Fei Lu ◽  
Hong Shan Yang ◽  
Ying Lai Yang
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Glass Transition Temperatures ◽  
Acrylate Copolymer ◽  
Amino Resin ◽  
Acrylate Resin ◽  
Oligomeric Silsesquioxane ◽  
Physical Blending ◽  
Better Than

An acrylate resin copolymerized with epoxy and amino resin was prepared in this paper, and its polyhedral oligomeric silsesquioxane (POSS) modified nanocomposites were fabricated via physical blending. Results showed that glass transition temperature of the acrylate copolymer was about 7.9 oC via DSC. Dispersion of nanocomposites with aminopropyllsobutyl POSS is better than those with Octalsobutyl POSS. Moreover, glass transition temperatures of the nanocomposites with POSS are close to the acrylate copolymer matrix.

scholarly journals Core/Clad Phosphate Glass Fibres Containing Iron and/or Titanium

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ifty Ahmed ◽  
S. S. Shaharuddin ◽  
N. Sharmin ◽  
D. Furniss ◽  
C. Rudd
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Tensile Modulus ◽  
Average Diameter ◽  
Phosphate Glasses ◽  
Dissolution Medium ◽  
The Core ◽  
Controllable Degradation

AbstractPhosphate glasses are novel amorphous biomaterials due to their fully resorbable characteristics, with controllable degradation profiles. In this study, phosphate glasses containing titanium and/or iron were identified to exhibit sufficiently matched thermal properties (glass transition temperature, thermal expansion coefficient and viscosity) which enabled successful co-extrusion of glass billets to form a core/clad preform. The cladding composition for the core/clad preforms were also reversed. Fe clad and Ti clad fibres were successfully drawn with an average diameter of between 30~50 μm. The average cladding annular thickness was estimated to be less than 2 μm. Annealed core/clad fibres were degraded in PBS for a period of 27 days. The strength of the Fe clad fibres appeared to increase from 303 ± 73 MPa to 386 ± 45 MPa after nearly 2 weeks in the dissolution medium (phosphate buffered solution) before decreasing by day 27. The strength of the Ti clad fibres revealed an increase from 236 ± 53 MPa to 295 ± 61 MPa when compared at week 3. The tensile modulus measured for both core/clad fibres ranged between 51 GPa to 60 GPa. During the dissolution study, Fe clad fibres showed a peeling mechanism compared to the Ti clad fibres.

Observation of Glass Transition Temperatures in Polymeric Thin Films by Wafer Curvature Measurements

1991 ◽  
Vol 239 ◽  
Author(s):  
P. H. Townsend ◽  
B. S. Huber ◽  
D. S. Wang
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Polymer Network ◽  
Cross Linking ◽  
Positional Isomers ◽  
Glass Transition Temperatures ◽  
Thin Coatings ◽  
Polymeric Thin Films ◽  
Curvature Measurements

ABSTRACTWafer bending measurements have been used to study the glass transition temperature, Tg, of thin coatings of polystyrene and polycarbonate on Si wafers. The observed values of Tg agree with DSC and TMA measurements on bulk samples. The evolution of the substrate curvature has been used to examine the behavior of Tg in thin epoxy films and coatings derived from divinylsiloxane bisbenzocyclobutene, mixed stereo and positional isomers of 1, 3-bis(2-bicyclo[4.2.0]octa-1, 3, 5-trien-3-ylethenyl)-1, 1, 3, 3-tetramethyl disitoxane (CAS 117732–87–3). The dependence of the Tg of the epoxide coatings is studied as a function of the cross-linking. The evolution of the Tg in the benzocyclobutene coating is found to be a monotonie function of the level of conversion of the polymer network.

Thermal Properties of Bi2O3-B2O3-ZnO Glass System

2006 ◽  
Vol 510-511 ◽  
pp. 578-581 ◽  
Author(s):  
Yu Jin Kim ◽  
Seong Jin Hwang ◽  
Hyung Sun Kim
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Lead Oxide ◽  
Lead Free ◽  
Oxide Glasses ◽  
Glass Formation Region ◽  
Formation Region ◽  
Lower Glass Transition Temperature

Oxide glasses having lower glass transition temperature are widely used in electric devices. The oxide glasses usually contain lead oxide. Recently, lead oxide glasses have been replaced with lead-free oxide glasses because of the environmental pollution. We investigated the thermal properties and the glass formation region in the Bi2O3-B2O3-ZnO ternary system. The results showed that the ratio of Tg/Tl of the bismate glasses is around 0.55, which is lower than the value of ratio 0.67, the two-third rule (Tg/ Tl=2/3)

scholarly journals Obtaining orange juice–maltodextrin powders without structure collapse based on the glass transition temperature and degree of polymerization

2017 ◽  
Vol 16 (1) ◽  
pp. 61-69 ◽  
Author(s):  
María Z. Saavedra–Leos ◽  
César Leyva-Porras ◽  
Claudia Alvarez-Salas ◽  
Francisco Longoria-Rodríguez ◽  
Ana L. López-Pablos ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Orange Juice ◽  
Degree Of Polymerization ◽  
Structure Collapse

Properties and Structure of Elastomers

1966 ◽  
Vol 39 (4) ◽  
pp. 881-896 ◽  
Author(s):  
Joginder Lal ◽  
Kenneth W. Scott
Keyword(s):  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Alkyl Group ◽  
Side Chain ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Dynamic Mechanical ◽  
Alkyl Ethers

Abstract The glass transition temperatures of high molecular weight poly (vinyl n-alkyl ethers) decrease with increasing length of the n-alkyl group. On lengthening the n-alkyl group, 14 per cent of the specific volume increase is free volume. Branching or substitution in the alkyl group of the polymer increases the Tg value. A comparison of poly (vinyl n-alkyl ethers) and polymers of normal α-olefins shows that an ether group and a methylene group in the side chain are equivalent in influencing the glass transition temperature. We have varied systematically the side chain alkyl group in poly (vinyl alkyl ethers) and evaluated at 3 different temperatures the influence of these variations on the dynamic properties of the vulcanizates of these polymers. The relative position of the curves, relating dynamic resilience to dynamic modulus of these polymers, is generally in the order of their glass transition temperatures. The dynamic mechanical property data on poly (vinyl n-pentyl ether) and poly (vinyl 2-ethylhexyl ether), which have the same glass transition temperature, fall on a common curve characteristic of the temperature of measurement. Apparently, the Tg is a major factor in correlating the dynamic mechanical behavior of these elastomers. The size and shape of the alkyl group appear to be reflected primarily in their effect on the Tg. Polysulfidic crosslinks are not essential for the attainment of high tensile strength in natural rubber vulcanizates cured with a sulfur-diphenylguanidine system. Data for the samples which had lost significant amounts of polysulfidic crosslinks by reaction with triphenylphosphine fitted a curve of tensile strength as a function of 300 per cent modulus for the control samples.

scholarly journals Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

2015 ◽  
Vol 59 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Sławomir Bakier ◽  
Kamila Goderska ◽  
Krzysztof Mansfeld
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermodynamic Properties ◽  
Sugar Content ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Complete Liquefaction

Abstract Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p<0.05) and ranged from -49.7°C (polyfloral) to -34.8°C (sunflower). There was a strong correlation between the Tg values and the moisture content in honey (r = -0.94). The degree of crystallisation of the honey also influenced the Tg values. It has been shown that the presence or absence of sugar crystals influenced the glass transition temperature. For the decrystallised honeys, the Tg values were 6 to 11°C lower than for the crystallised honeys. The more crystallised a honey was, the greater the temperature difference was between the decrystallised and crystallized honey. In conclusion, to obtain reliable DSC results, it is crucial to measure the glass transition after the complete liquefaction of honey.

Sign in / Sign up

Export Citation Format

Share Document