Multiple Glass Transitions in Butadiene—Acrylonitrile Copolymers. II. Formation of Incompatible Phases during Copolymerization

1973 ◽  
Vol 46 (4) ◽  
pp. 1087-1102 ◽  
Author(s):  
A. H. Jorgensen ◽  
L. A. Chandler ◽  
E. A. Collins
Keyword(s):  
Glass Transition ◽  
Published Data ◽  
Transition Temperatures ◽  
Glass Transitions ◽  
Glass Transition Temperatures ◽  
Mechanical Measurements ◽  
Nitrile Rubbers ◽  
Polymer Compatibility ◽  
Two Phases ◽  
Acrylonitrile Copolymers

Abstract Differential Thermal Analysis and Dynamic Mechanical measurements show that the presence of two glass transition temperatures in nitrile rubbers is not unusual. Two glass transition temperatures occur in all commercial non-crosslinked butadiene-acrylonitrile rubbers of less than 35 per cent acrylonitrile even though they have gone previously undetected. We have investigated the changes in composition and glass transition temperatures during the course of the copolymerization. The composition versus conversion results were in agreement with previously published data. Fractionation and polymer-polymer compatibility experiments were used to demonstrate the presence of two incompatible phases of different acrylonitrile content, corresponding to the glass transitions of the original co-polymer. The mechanism for the formation of these two phases is discussed.

Multiple Glass Transitions in Butadiene-Acrylonitrile Copolymers

1970 ◽  
Vol 43 (6) ◽  
pp. 1465-1472 ◽  
Author(s):  
L. A. Chandler ◽  
E. A. Collins
Keyword(s):  
Molecular Structure ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Order Transition ◽  
Transition Temperatures ◽  
Glass Transitions ◽  
Second Order Transition ◽  
Two Phases ◽  
Polymerization Conditions ◽  
Acrylonitrile Copolymers

Abstract The second order transition temperatures (Tg) have been determined for a range of compositions of polybutadiene-acrylonitrile copolymers. It was found that copolymers having more than 36 per cent acrylonitrile had a single Tg while copolymers with less than 36 per cent acrylonitrile had two main Tg's. The analyses were carried out with differential thermal analysis (DTA). The two Tg's are interpreted as the result of incompatible phases which differ in BD and VCN ratio. The presence of two phases is discussed in terms of polymerization conditions and molecular structure.

scholarly journals Kinetically controlled glass transition measurement of organic aerosol thin films using broadband dielectric spectroscopy

2018 ◽  
Vol 11 (6) ◽  
pp. 3479-3490 ◽  
Author(s):  
Yue Zhang ◽  
Shachi Katira ◽  
Andrew Lee ◽  
Andrew T. Lambe ◽  
Timothy B. Onasch ◽  
...  
Keyword(s):  
Glass Transition ◽  
Dielectric Spectroscopy ◽  
Organic Aerosols ◽  
Transition Temperatures ◽  
Glass Transitions ◽  
Relaxation Rates ◽  
Heating Rates ◽  
Glass Transition Temperatures ◽  
Broadband Dielectric Spectroscopy ◽  
Kinetically Controlled

Abstract. Glass transitions from liquid to semi-solid and solid phase states have important implications for reactivity, growth, and cloud-forming (cloud condensation nuclei and ice nucleation) capabilities of secondary organic aerosols (SOAs). The small size and relatively low mass concentration of SOAs in the atmosphere make it difficult to measure atmospheric SOA glass transitions using conventional methods. To circumvent these difficulties, we have adapted a new technique for measuring glass-forming properties of atmospherically relevant organic aerosols. Aerosol particles to be studied are deposited in the form of a thin film onto an interdigitated electrode (IDE) using electrostatic precipitation. Dielectric spectroscopy provides dipole relaxation rates for organic aerosols as a function of temperature (373 to 233 K) that are used to calculate the glass transition temperatures for several cooling or heating rates. IDE-enabled broadband dielectric spectroscopy (BDS) was successfully used to measure the kinetically controlled glass transition temperatures of aerosols consisting of glycerol and four other compounds with selected cooling and heating rates. The glass transition results agree well with available literature data for these five compounds. The results indicate that the IDE-BDS method can provide accurate glass transition data for organic aerosols under atmospheric conditions. The BDS data obtained with the IDE-BDS technique can be used to characterize glass transitions for both simulated and ambient organic aerosols and to model their climate effects.

scholarly journals Kinetic Controlled Glass Transition Measurement of Organic Aerosol Thin Films Using Broadband Dielectric Spectroscopy

2018 ◽  
Author(s):  
Yue Zhang ◽  
Shachi Katira ◽  
Andrew Lee ◽  
Andrew T. Lambe ◽  
Timothy B. Onasch ◽  
...  
Keyword(s):  
Glass Transition ◽  
Dielectric Spectroscopy ◽  
Solid Phase ◽  
Organic Aerosols ◽  
Transition Temperatures ◽  
Glass Transitions ◽  
Relaxation Rates ◽  
Cooling Rates ◽  
Glass Transition Temperatures ◽  
Broadband Dielectric Spectroscopy

Abstract. Glass transitions from liquid to semi-solid and solid phase states have important implications for reactivity, growth, and cloud forming (cloud condensation nuclei and ice nucleation) capabilities of secondary organic aerosols (SOA). The small size and relatively low mass concentration of SOA in the atmosphere make it difficult to measure atmospheric SOA glass transitions using conventional methods. To circumvent these difficulties, we have adopted a new technique for measuring glass forming properties of atmospherically relevant organic aerosols. Aerosol particles to be studied are deposited in the form of a thin film onto an interdigitated electrode (IDE) using electrostatic precipitation. Dielectric spectroscopy provides dipole relaxation rates for organic aerosols as a function of temperature (373 to 233 K) that are used to calculate the glass transition temperatures for several cooling rates. IDE-enabled broadband dielectric spectroscopy (BDS) was successfully used to measure the kinetically controlled glass transition temperatures of glycerol and citric acid aerosols with selected cooling rates. The glass transition results agree well with available literature data for these two compounds. The results indicate that the IDE-BDS method can provide accurate glass transition data for organic aerosols under atmospheric conditions. The BDS data obtained with the IDE-BDS technique can be used to characterize glass transitions for both simulated and ambient organic aerosols and to model their climate effects.

Properties of Random PSF/PES Copolymers as High-Performance Polymers

2011 ◽  
Vol 217-218 ◽  
pp. 1606-1610
Author(s):  
Dong Jiang ◽  
Xiao Ran Zhang ◽  
Yan Mei Ma ◽  
Cheng You Ma
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Glass Transition ◽  
High Performance ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Elongation At Break ◽  
Glass Transition Temperatures ◽  
High Performance Polymers ◽  
Diphenyl Sulfone

A series of random polysulfone/polyethersulfone (PSF/PES) copolymers were synthesized by the polycondensation of 4, 4'-isopropylidendiphenol, 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone in the presence of K2CO3. We obtained a series of copolymers by changing the molar ratio of 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-isopropylidendiphenol (it was marked as the ratio of S:A). The copolymers have the similar solubility with polyethersulfone. They also have high glass transition temperatures (Tg: 199°C~229°C) and 5% weight loss temperatures (4, 4'-isopropylidendiphenol: 4, 4΄-dihyolroxy diphenyl sulfone=1:1, Td5=497°C). At the same time the elongation at break is much higher than that of PES, while the tensile strength is a little lower than that of PES.

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