Effect of Primidone Concentration on Glass Transition Temperature and Dissolution of Solid Dispersion Systems Containing Primidone and Citric Acid

1977 ◽  
Vol 66 (6) ◽  
pp. 825-828 ◽  
Author(s):  
M.P. Summers ◽  
R.P. Enever
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Solid Dispersion ◽  
Dispersion Systems

Citric acid grafting onto polyurethane for the control of molecular interactions and water compatibility

2016 ◽  
Vol 48 (8) ◽  
pp. 691-710
Author(s):  
Yong-Chan Chung ◽  
Hyeryoung Yoon ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Low Temperature ◽  
Molecular Interactions ◽  
Water Permeability ◽  
Enthalpy Change ◽  
Low Temperature Flexibility ◽  
Grafting Onto

Citric acid (CA) was used as a grafted group onto polyurethane (PU) to form a CA-grafted PU series, with a control PU series containing free CA prepared for comparison. With an increase in the CA content, the enthalpy change during the melting increased for the PU and CPU series, and the glass transition temperature increased with the increase in CA content for the PU series but not for the CPU series. The tensile strengths of the PU series sharply increased with the CA content, whereas those of the CPU series did not. The PU series demonstrated better low-temperature flexibility and water permeability than the unmodified PU.

Preparation and Charaterization of Poly(1,4–Butanediol-Citrate) Elastomers and CdTe/Poly(1,4–Butanediol-Citrate) Composite Bioelastomers

2014 ◽  
Vol 1053 ◽  
pp. 482-488
Author(s):  
Li Jiang ◽  
Ai Miao Qin ◽  
Lei Liao ◽  
Xiu Lan Wu ◽  
Xin Liang Yu
Keyword(s):  
Tissue Engineering ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Polymerization Time ◽  
Structures And Properties ◽  
Soft Tissue Engineering ◽  
Fluorescent Spectra ◽  
High Fluorescence

Poly (1, 4–butanediol-citrate) elastomer (PBC) network polyester bioelastomer and high fluorescent CdTe/PBC nanocomposite bioelastomer were obtained by melting polycondensation with citric acid and monomer 1, 4-Butylene glycol as monomers. The structures and properties of the products were characterized by FTIR,DSC and fluorescent spectra, etc. It shows that the glass transition temperature of the PBC and CdTe/PBC were all lower than 0°C. Both PBC and CdTe/PBC were amorphous, transparent and highly flexible. They also have good hydrophilicity, degradation, and stability in dimensions. The biodegradation and water uptake of elastomers PBC and CdTe/PBC could be modulated by adjusting the monomers ratio and post-polymerization time. CdTe/PBC has high fluorescence and is expected to be useful in soft tissue engineering with the function of fluorescence biomarker.

scholarly journals Toward closure between predicted and observed particle viscosity over a wide range of temperatures and relative humidity

2021 ◽  
Vol 21 (2) ◽  
pp. 1127-1141
Author(s):  
Sabin Kasparoglu ◽  
Ying Li ◽  
Manabu Shiraiwa ◽  
Markus D. Petters
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Relative Humidity ◽  
Water Uptake ◽  
Equilibrium Phase ◽  
Relaxation Method ◽  
Wide Range ◽  
Temperature And Humidity

Abstract. Atmospheric aerosols can exist in amorphous semi-solid or glassy phase states whose viscosity varies with atmospheric temperature and relative humidity. The temperature and humidity dependence of viscosity has been hypothesized to be predictable from the combination of a water–organic binary mixing rule of the glass transition temperature, a glass-transition-temperature-scaled viscosity fragility parameterization, and a water uptake parameterization. This work presents a closure study between predicted and observed viscosity for sucrose and citric acid. Viscosity and glass transition temperature as a function of water content are compiled from literature data and used to constrain the fragility parameterization. New measurements characterizing viscosity of sub-100 nm particles using the dimer relaxation method are presented. These measurements extend the available data of temperature- and humidity-dependent viscosity to −28 ∘C. Predicted relationships agree well with observations at room temperature and with measured isopleths of constant viscosity at ∼107 Pa s at temperatures warmer than −28 ∘C. Discrepancies at colder temperatures are observed for sucrose particles. Simulations with the kinetic multi-layer model of gas–particle interactions suggest that the observed deviations at colder temperature for sucrose can be attributed to kinetic limitations associated with water uptake at the timescales of the dimer relaxation experiments. Using the available information, updated equilibrium phase-state diagrams (-80∘C<T<40∘C, temperature, and 0%<RH<100%, relative humidity) for sucrose and citric acid are constructed and associated equilibration timescales are identified.

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