Phase Separation Behaviors Of Polyimide Blends

1998 ◽  
Vol 511 ◽  
Author(s):  
C. H. Ryu ◽  
Y. C. Bae
Keyword(s):  
Phase Transition ◽  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Critical Temperature ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Phase Transition Temperatures ◽  
Phase Behaviors ◽  
System Phase

ABSTRACTWe investigated phase behaviors of polyimide blends such as polyethermide(PEI)/polystyrene(PS), PEI/polyamideimide(PAI), PEI/polyethyleneoxide(PEO), and PAI/PEO systems. Our sample systems exhibited lower critical solution temperature(LCST) phase behaviors. In the PEI/PS system, phase transition occurred near or above the glass transition temperature(Tg) of PS and the critical temperature of the system increased with decreasing molecular weight of PS. For PEI/PAI and PEI/PEO systems, the critical temperature of PEI/PAI system is higher than that of PEI/PEO system. Phase transition temperatures of PAI/PEO systems appeared near or below the melting point of PEO.

scholarly journals The Properties of Thermosensitive Zwitterionic Sulfobetaine NIPAM-co-DMAAPS Polymer and the Hydrogels: The Effects of Monomer Concentration on the Transition Temperature and Its Correlation with the Adsorption Behavior

2020 ◽  
Vol 20 (2) ◽  
pp. 324
Author(s):  
Eva Oktavia Ningrum ◽  
Agus Purwanto ◽  
Galuh Chynintya Rosita ◽  
Asep Bagus
Keyword(s):  
Molecular Structure ◽  
Phase Transition ◽  
Transition Temperature ◽  
Lower Critical Solution Temperature ◽  
Monomer Concentration ◽  
Adsorption Behavior ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Adsorption Amount

The properties of N-isopropylacrylamide copolymerized with N,N-dimethyl(acrylamidopropyl)ammonium propane sulfonate [poly(NIPAM-co-DMAAPS)] prepared with various monomer ratios such as transition temperature, molecular structure, viscosity were systematically investigated in water and Zn(NO3)2 solution. Poly(NIPAM-co-DMAAPS) in water and Zn(NO3)2 solution exhibited a phase transition with a lower critical solution temperature (LCST). The higher ratio of NIPAM monomer in poly(NIPAM-co-DMAAPS), the lower the LCST of the polymer. Furthermore, the transition temperature of poly(NIPAM-co-DMAAPS) with a lower NIPAM concentration were not confirmed both in water nor Zn(NO3)2 solution. The more increase the NIPAM concentration used in the preparation, the more increase the polymer viscosity. Moreover, the more increase the adsorption amount of ions onto the gel, the more increase the polymer transmittance as well.

A polyelectrolyte-containing copolymer with a gas-switchable lower critical solution temperature-type phase transition

2019 ◽  
Vol 10 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Jin-Jin Li ◽  
Yin-Ning Zhou ◽  
Zheng-Hong Luo ◽  
Shiping Zhu
Keyword(s):  
Phase Transition ◽  
Cloud Point ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Type Phase

A polyelectrolyte-containing copolymer with a CO2/N2-switchable cloud point, resulting from the gas-induced alternation of hydrophilicity, was prepared.

Imide Oligomers Containing Pendent and Terminal Phenylethynyl Groups—II

1998 ◽  
Vol 10 (3) ◽  
pp. 273-283 ◽  
Author(s):  
J W Connell ◽  
J G Smith ◽  
P M Hergenrother
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Average Molecular Weight ◽  
Adhesive Tape ◽  
High Glass Transition Temperature ◽  
Compressive Properties ◽  
Compression Moulding ◽  
Imide Oligomers

As part of a programme to develop high-performance/high-temperature structural resins for aeronautical applications, imide oligomers containing pendent and terminal phenylethynyl groups were prepared, characterized and the cured resins evaluated as composite matrices. The oligomers were prepared at a calculated number-average molecular weight of 5000 g mol−1 and contained 15–20 mol% pendent phenylethynyl groups. In previous work, an oligomer containing pendent and terminal phenylethynyl groups exhibited a high glass transition temperature (∼313 °C), and laminates therefrom exhibited high compressive properties, but processability, fracture toughness, microcrack resistance and damage tolerance were less than desired. In an attempt to improve these deficiencies, modifications in the oligomeric backbone involving the incorporation of 1,3-bis(3-aminophenoxy)benzene were investigated as a means of improving processability and toughness without detracting from the high glass transition temperature and high compressive properties. The amide acid oligomeric solutions were prepared in N-methyl-2-pyrrolidinone and were subsequently processed into imide powder, thin films, adhesive tape and carbon fibre prepreg. Neat resin plaques were fabricated from imide powder by compression moulding. The maximum processing pressure was 1.4 MPa and the cure temperature ranged from 350 to 371 °C for 1 h for the mouldings, adhesives, films and composites. The properties of the 1,3-bis(3-aminophenoxy)benzene modified cured imide oligomers containing pendent and terminal phenylethynyl groups are compared with those of previously prepared oligomers containing pendent and terminal phenylethynyl groups of similar composition and molecular weight.

Phase transition in non-crystalline solids viewed from heating

1995 ◽  
Vol 398 ◽  
Author(s):  
K. Nakayama ◽  
K. Kojima ◽  
N. Takahashi ◽  
Y. Masaki ◽  
A. Kitagawa ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Heating Rate ◽  
Transient Phase ◽  
Disordered Structures ◽  
Fragmentation Processes ◽  
Scaling Rule

ABSTRACTThe heating-rate dependence of crystallization temperature, Tc, and the glass transition temperature, Tg, is studied from the view points of nucleation and fragmentation processes in disordered structures. Tc and Tg are expected to increase monotonically with heating rate. Such behaviors of Tc and Tg are classified into four characteristic regions with respect to the heating rate. Results are summarized in the Transient Phase Diagram where Tc and Tg are given as a function of heating rate. The scaling rule in the Transient Phase Diagram is given.

scholarly journals Unexpected LCST-type phase behaviour of a poly(vinyl thiazolium) polymer in acetone

RSC Advances ◽  
2016 ◽  
Vol 6 (62) ◽  
pp. 57117-57121 ◽  
Author(s):  
Konrad Grygiel ◽  
Weiyi Zhang ◽  
Christophe Detrembleur ◽  
Jiayin Yuan
Keyword(s):  
Phase Transition ◽  
Lower Critical Solution Temperature ◽  
Acetone Solution ◽  
Phase Behaviour ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Type Phase

A poly(vinyl thiazolium) polymer in acetone solution exhibited an unexpected lower critical solution temperature (LCST)-type phase transition.

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