Fluorinated Polyimide Block Copolymers

1991 ◽  
Vol 227 ◽  
Author(s):  
J. W. Labadic ◽  
M. I. Sanchcz ◽  
Y. Y. Cheng ◽  
James L. Hedrick
Keyword(s):  
Molecular Weight ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Block Copolymers ◽  
Aryl Ether ◽  
Moisture Sensitivity ◽  
Fluorinated Polyimide ◽  
Aryl Ethers

ABSTRACTBlock copolymers based on the poly(amic ester) of poly(4,4′-oxydiphenylene-pyromellitide) and perfluoroalkylene aryl ethers were synthesized from preformed amine terminated perfluoroalkylene aryl ether oligomers. Fluoropolymer structure, wt% incorporation, and molecular weight were varied. Reduction in the dielectric constant to 2.8–2.9 and reduced moisture sensitivity were observed for block copolymers with 55 wt.% poly(perfluoroalkylene aryl ether) content without significant compromise of mechanical or thermal properties.

Synthesis and thermal properties of triblock copolymers of methyl methacrylate using combination of anionic and controlled radical polymerization: Poly(methyl methacrylate) center block bearing different microstructures

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhengji Song ◽  
Carole Pelletier ◽  
Yinghua Qi ◽  
Jasim Ahmed ◽  
Sunil K. Varshney ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Triblock Copolymers ◽  
Controlled Radical Polymerization ◽  
Alkyl Methacrylate ◽  
Poly Methyl Methacrylate ◽  
H Nmr

AbstractABA and/or ABC type triblock copolymers were synthesized by living anionic and controlled radical polymerization in which poly(methyl methacrylate) was used as central block. The structural composition of these block copolymers were determined by 1H NMR. The block length/molecular weight and microstructure of these polymers were measured by SEC. The microstructure of resultant central alkyl methacrylate block can be tailored from highly syndiotactic to highly isotactic structure by varying the solvent and/or initiator. The thermal and rheological properties of center poly(methyl methacrylate) block and poly(styreneb- methyl methacrylate-b- styrene) tri block copolymers were studied in detail.

Synthesis and Properties of a Novel Thermostable Polymer: Fluorinated Polycarbodiimide

1997 ◽  
Vol 9 (4) ◽  
pp. 385-395 ◽  
Author(s):  
Amane Mochizukiy ◽  
Michie Sakamotoy ◽  
Masahiro Yoshiokay ◽  
Yuji Hottay ◽  
Takahiro Fukuokay ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Decomposition ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Thermostable Polymer ◽  
Lower Dielectric Constant ◽  
Wide Range ◽  
Solution Polycondensation

A new fluorinated linear polycarbodiimide (F-PCD) was synthesized by solution polycondensation of a new fluorinated diisocyanate monomer, 4″, 4″′-(hexafluoroisopropylidene) bis(4-phenoxyphenyl isocyanate) (HPI) in the presence of 3-methyl-1-phenyl-2-phospholene-1-oxide (PMO). HPI was prepared from 4″, 4″′-(hexafluoroisopropylidene)bis(4-phenoxyaniline) (HPA) by three steps. The reaction of HPA with phenyl chloroformate gave the corresponding carbamate, which upon reaction with trimethylsilylchloride (TMS-Cl)-triethylamine (TEA), followed by thermal decomposition, provided HPI. The polymer having a number average molecular weight up to 8400 was obtained in quantitative yield. Thermal properties were investigated and we found that the polymer has a higher glass transition temperature ( Tg)upto 230 °C, and a lower dielectric constant at 2.98 at 1 MHz than the conventional polycarbodiimides (PCDs). The linear F-PCD was soluble in a wide range of common organic solvents such as toluene and dichloromethane.

Novel soluble polyimides containing pyridine and fluorinated units: preparation, characterization, and optical and dielectric properties

RSC Advances ◽  
2016 ◽  
Vol 6 (26) ◽  
pp. 21662-21671 ◽  
Author(s):  
Weibing Dong ◽  
Yue Guan ◽  
Dejing Shang
Keyword(s):  
Dielectric Constant ◽  
Thermal Properties ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
Mechanical And Thermal Properties ◽  
Polyimide Films ◽  
Low Dielectric

To acquire low dielectric constant polyimide films with good mechanical and thermal properties and low CTE applied in microelectronic fields, three novel polyimides containing pyridine and –C(CF3)2– groups were firstly designed and synthesized.

Synthesis and Characterization of Poly(Aryl Ether Quinoxaline)s with Controlled Molecular Weight

2011 ◽  
Vol 391-392 ◽  
pp. 826-829
Author(s):  
Song Ya Zhang ◽  
Zhong Xiao Li ◽  
Jia Ling Pu
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Strong Acid ◽  
Decomposition Temperature ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Aryl Ether ◽  
Good Solubility ◽  
Step Procedure

Novel poly(aryl ether quinoxaline)s (PEQs) were prepared via a two-step procedure. First, poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4’-difluorobenzil and 4,4’-isopropylidenediphenol.Then, PEB was reacted with 1,2-diaminobenzene and 4,4'-oxydibenzene-1,2-diamine to give the PEQs. The molecular weight of the PEQs could be adjusted easily by varying the molar ratio of 1,2-diaminobenzene to 4,4'-oxydibenzene-1,2-diamine. The PEQs exhibited good solubility in common organic solvents such as NMP, DMAc, DMF, cyclohexanone and chloroform. In addition, the PEQs also had high glass transition (Tg) temperatures and good thermal properties, with an initial thermal decomposition temperature above 475 oC and glass transition temperatures above 210 oC. They also exhibited excellent resistance to strong acid and alkali.

Elastomeric Polycarbonate Block Copolymers

1965 ◽  
Vol 38 (2) ◽  
pp. 431-449
Author(s):  
Eugene P. Goldberg
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Bisphenol A ◽  
Flexural Modulus ◽  
Softening Temperature ◽  
Thermoplastic Elastomers ◽  
Partial Replacement ◽  
Initial Increase ◽  
Copolymer Composition ◽  
Moderate Degree

Abstract Polycarbonate block copolymers were prepared by phosgenating pyridine solutions of polyether glycol-bisphenol-A mixtures. Copolycarbonates derived from poly(oxyethylene) glycols (Carbowaxes) were studied in detail for property-structure effects as a function of glycol molecular weight (1000–20,000) and copolymer composition (5–70 weight per cent or 0.3–10.0 mole per cent of a 4000 molecular weight glycol). Remarkable strength (>7000 psi) and snappy elasticity (>90 per cent immediate recovery) were observed at poly(oxyethylene) block concentrations greater than 3 mole per cent. These thermoplastic elastomers also exhibited high softening temperatures (>180° C) and tensile elongations up to about 700 per cent. Both Tg and softening temperature varied linearly with comonomer mole ratio over the composition range studied, with Tg displaying much greater polyether concentration sensitivity. It is suggested that the observed property effects result to a large extent from the variation in poly(bisphenol-A carbonate) block length that accompanies the changing of copolymer composition. An initial increase in flexural modulus (stiffness) was observed at low polyether concentrations (0–1 mole per cent). This phenomenon is considered to be related to similar modulus effects found in plasticized rigid thermoplastics at low plasticizer concentrations. A moderate degree of molecular order, due to bisphenol carbonate segments rather than the normally crystalline polyether, was detected by x-ray analysis. Elastomeric carbonate-carboxylate tetrapolymers were also prepared by partial replacement of carbonate with isophthalate, terephthalate or adipate linkages in polyether-bisphenol systems. The dramatic softening temperature depression observed in this class of polymers is attributed to the disruption of long bisphenol carbonate block sequences that exist in the simpler polyether glycol-bisphenol carbonate copolymers.

Graft modification in bamboo cellulose nanofibrils: An effective option to improve compatibility and tunable surface energy

2021 ◽  
Author(s):  
Carlos Alejandro Rodríguez-Ramírez ◽  
Alain Dufresne ◽  
Norma Beatriz D'Accorso ◽  
Nancy Garcia
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Cellulose Nanofibrils ◽  
Value Added ◽  
Xrd Analysis ◽  
Low Molecular Weight ◽  
Mechanical And Thermal Properties ◽  
Graft Modification ◽  
Effective Option ◽  
20 Nm

Abstract In this work, from an endemic and non-significant value-added bamboo argentine, nanofibrils (CNFs) of 20 nm in width were obtained. These nanofibrils were chemical modified in surface with three simple steps using a noncommercial low molecular weight polylactic acid. The success of modification was confirmed by FTIR, TGA, DSC and XRD analysis. The modified nanofibrils were taken up for changing surface properties in films based on commercial PLA. The results show that dispersive (γ D/S) component of films increase of 34.7 mN/m to 36.1 mN/m after the addition of modified nanofibrils from 2 to 5% in formulation of the films, comparing with a physical blend. Interesting others result in physical, mechanical, and thermal properties of the nanocomposites, were reported.

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