Chemical synthesis of some Schiff base-type polymers containing pyrrole units

Simionescu, C. I.; Grigoraş, Mircea; Cianga, I.; Diaconu, I.; Farcas, Aurica

doi:10.1007/bf00308535

Cited by 25 publications

(8 citation statements)

References 5 publications

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“…When the azomethine groups are incorporated in to the polymer backbone, they exhibit good properties such as thermal stability [3,4], conductivity [5], fiber-forming ability [6,7], liquid crystalline behavior [8,9] and non-linear optical properties [10]. A drawback of the linear, aromatic rod-like poly(azomethine)s is their limited solubility in organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of New Polyamides with Substitutions in the Pendent Benzylidene Rings

Ravikumar¹,

Saravanan

Saravanamani

et al. 2009

Designed Monomers and Polymers

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Aromatic polyamides with azomethine groups present in the polymer with -Cl, -OCH 3 , -N(CH 3 ) 2 and -OH substitutions in the pendent benzylidene rings were synthesized through polycondensation of new aromatic dicarboxylic acids with aromatic diamines using the phosphorylation technique in DMF. Direct polymerization of the monomers benzylidenamino phenyl 2,5-dicarboxylic acid (M1), 4 -hydroxy benzylidenamino phenyl 2,5-dicarboxylic acid (M2), 4 -methoxy benzylidenamino phenyl 2,5-dicarboxylic acid (M3), 4 -chloro benzylidenamino phenyl 2,5-dicarboxylic acid (M4) and (N,N-dimethylamino) benzylidenamino phenyl 2,5-dicarboxylic acid (M5) was carried out with commercial diamines, 4,4 -methylenedianilene and 4,4-diaminobiphenyl, at 140 • C. FT-IR and 1 H-NMR spectroscopic analysis were used to characterize the monomers and polymers. The inherent viscosity values of polyamides are in the range 0.39-0.68. Due to the substitutions in the pendent benzylidene rings, the polymers show enhanced solubility. The thermal stability of the polyamides was evaluated using thermogravimetric analysis, and the thermogravimetric curves show the dependence of thermal stability on the nature of the substitutions in the benzylidene rings.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of New Polyamides with Substitutions in the Pendent Benzylidene Rings

Ravikumar¹,

Saravanan

Saravanamani

et al. 2009

Designed Monomers and Polymers

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“…In most cases, these conductive biomaterials are obtained in the form of blends or composites by using biodegradable polymers as matrices and an intrinsically conductive polymer, polypyrrole (PPy), as a conductive component because PPy has an acceptable biocompatibility with mammalian cells 16. In addition, since most of the copolymers that consist of PPy oligomers and other polymer oligomers either have a low conductivity or contain a high content of PPy oligomers,17–19 they are not suitable for conductive nerve conduits. To date, most polymers involved in this area are polyesters such as polylactide, polyglycolide, poly( ε ‐caprolactone), and their copolymers 20–23.…”

Section: Introductionmentioning

confidence: 99%

Electrically Conductive Poly(DL‐lactide)/Chitosan/Polypyrrole Complexes

Wan

Fang

et al. 2006

Macromol. Rapid Commun.

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Summary: The fabrication of novel conductive poly(DL‐lactide)/chitosan/polypyrrole complex membranes is reported. Using poly(DL‐lactide)/chitosan blends as matrices and polypyrrole as a conductive component, several kinds of membranes with various compositions are prepared. A percolation threshold of polypyrrole as low as 1.8 wt.‐% is achieved for some membranes by controlling the chitosan proportion between 40 and 50 wt.‐%. SEM images exhibit that the membranes with a low percolation threshold show a two‐phase structure which consists of poly(DL‐lactide) and chitosan phases. Dielectric measurements indicate that there is limited miscibility between the poly(DL‐lactide) and chitosan but polypyrrole is nearly immiscible with the other two components. Based on the structural characteristics of the membranes, the polypyrrole particles are suggested to be localized at the interface between two phases.

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“…Imine chemistry, also known as Schiff base chemistry, is the most often employed reversible covalent interaction, and includes two distinct processes: imine condensation/hydrolysis, and imine exchange . The wide variety of commercially available diamines and dialdehydes makes polyimines highly accessible functional polymers, with many well‐demonstrated unique functionalities . Polyimines, which are described as dynamers by Lehn, are stimuli‐responsive polymers, most notably exhibiting macroscopic responses to changes in pH .…”

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confidence: 99%

Heat‐ or Water‐Driven Malleability in a Highly Recyclable Covalent Network Polymer

et al. 2014

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as dynamers by Lehn, [ 25,26 ] are stimuli-responsive polymers, most notably exhibiting macroscopic responses to changes in pH. [ 27,28 ] Several imine-containing polymers have been demonstrated, including pH-responsive hydrogels [ 20 ] and a working organic light-emitting diode (OLED). [ 23 ] However, the potential of polyimines as malleable, mechanically resilient polymeric materials, as well as their processability, have remained largely unexplored. We envision that imine-linked polymers can take malleability in covalent network polymers to the next level of simplicity, affordability and practicality. Herein, we present the fi rst catalyst-free malleable polyimine which fundamentally behaves like a classic thermoset at ambient conditions yet can be reprocessed by application of either heat or water. This means that green, room temperature processing conditions are accessible for this important class of functional polymers.A crosslinked polyimine network was prepared from commercially available monomers: terephthaldehyde, diethylene triamine, and triethylene tetramine ( Figure 1 a). A polyimine fi lm was obtained by simply mixing the three above components in a 3:0.9:1.4 stoichiometry in the absence of any catalyst in a mixture of organic solvents (1:1:8, v/v/v, CH 2 Cl 2 /EtOAc/EtOH), then allowing the volatiles to evaporate slowly. Alternatively, the polymer can be obtained as a powder by using ethyl acetate as the only solvent. The polymerization reaction was confi rmed by infrared spectroscopy, which revealed that aldehyde end groups were consumed while imine linkages were formed ( Figure S2, Supporting Information). The resulting translucent polymer is hard and glassy at room temperature ( T g is 56 °C) ( Figure S1, Supporting Information) and has a modulus of near 1 GPa with stress at break of 40 MPa ( Figure S3, Supporting Information).The time and temperature dependent relaxation modulus of the polyimine fi lm was tested to characterize the heat-induced malleability. Figure 1 b depicts the results of a series of relaxation tests over a wide range of temperatures (50-127.5 °C) on a double logarithmic plot. Specifi cally, at 80 °C, the bond exchange reaction is initiated and the normalized relaxation modulus is decreased from 1 to 0.11 within 30 min, indicating an 89% release of the internal stress within the thermoset polymer. By shifting each relaxation curve horizontally with respect to a reference temperature at 80 °C, a master relaxation curve was constructed (Figure 1 c), which indicates the stress relaxation of the polyimine follows the classic time-temperature superposition (TTSP) behavior. The plot of time-temperature shift factors as a function of temperature (Figure 1 d) shows that the polyimine's stress-relaxation behavior exhibits Arrheniuslike temperature dependence. Using the extrapolation, we calculated that while it takes 30 min for the stress to be relaxed by ca. 90% at 80 °C, the same process would take ca. 480 days at room temperature. The polyimine is thus the fi rst reported

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Chemical synthesis of some Schiff base-type polymers containing pyrrole units

Cited by 25 publications

References 5 publications

Synthesis and Characterization of New Polyamides with Substitutions in the Pendent Benzylidene Rings

Synthesis and Characterization of New Polyamides with Substitutions in the Pendent Benzylidene Rings

Electrically Conductive Poly(DL‐lactide)/Chitosan/Polypyrrole Complexes

Heat‐ or Water‐Driven Malleability in a Highly Recyclable Covalent Network Polymer

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