Photocrosslinkable copolyesters: Poly(alkylene terephthalate-co-1,4-phenylene bisacrylate)

Vargas, Marian; Collard, David M.; Liotta, Charles L.; Schiraldi, David A.

doi:10.1002/(sici)1099-0518(20000615)38:12<2167::aid-pola50>3.0.co;2-7

Cited by 11 publications

(10 citation statements)

References 28 publications

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“…As can be seen in the figure, the IR spectra of these polymers are very similar, except for some differences in the peak intensities. The observed IR bands were assigned according to the results previously reported for PDA and its derivatives 28–30. The IR bands at 2956–2960 and 2875 cm −1 are due respectively to the asymmetric and symmetric CH stretching vibrations of the methyl ends of the n ‐alkyl side groups.…”

Section: Resultsmentioning

confidence: 89%

Synthesis and properties of photoalignable aromatic polyesters containing phenylenediacrylate units in their backbones and n‐alkyl moieties in their side groups

Lee

Ree

2004

J. Polym. Sci. A Polym. Chem.

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A series of poly[oxy(4‐n‐alkyl‐3,5‐benzoate)oxy‐1,4‐phenylenediacryloyl]s (PPDA‐CnBZ polymers) with high molecular weights was synthesized. These polymers exhibit excellent solubility in some common organic solvents and produce good quality films using conventional spin‐casting and drying processes. The polymers are thermally stable up to 357–362 °C in a nitrogen atmosphere; their glass transition temperatures are greater than 121 °C. The photoreactions and photoalignments of the polymers were investigated using ultraviolet‐visible and infrared spectroscopy, and their liquid crystal (LC) alignment properties were examined. The phenylenediacrylate (PDA) chromophores in the polyesters were found to mainly undergo photocyclization upon ultraviolet light irradiation. Irradiation of the polyester films with linearly polarized ultraviolet light (LPUVL) induces preferential orientation of the polymer main chains, while the unreacted PDA chromophores are aligned along the direction perpendicular to the electric vector of the LPUVL. All the films irradiated with LPUVL were found to align LCs in a direction perpendicular to the electric vector of the LPUVL. Moreover, these LC alignments persisted even on irradiated films annealed at temperatures up to 210 °C, which is much higher than the glass transition temperatures of the polyesters. These LC alignment characteristics are due to the anisotropic interactions of the LC molecules with the oriented polymer chains and with the unreacted PDA chromophores. LC alignments on the polyester film surfaces have homeotropic to homogeneous characteristics, depending on the length of the n‐alkyl side group, providing strong evidence that the n‐alkyl side groups of the polyesters play a critical role in determining the pretilt angles of the LCs. The LC pretilt angles were also found to be influenced by the thermal annealing history of the irradiated films. In summary, the excellent properties of the PPDA‐CnBZ polymers make them promising candidate materials for use as LC alignment layers in advanced LC display devices. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1322–1334, 2004

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Section: Resultsmentioning

confidence: 89%

Synthesis and properties of photoalignable aromatic polyesters containing phenylenediacrylate units in their backbones and n‐alkyl moieties in their side groups

Lee

Ree

2004

J. Polym. Sci. A Polym. Chem.

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“…UV irradiation alone on PET did show chain scissions rather than crosslinking under oxidative conditions. 18 Some copolyesters such as poly(alkylene terephthalate-co-1,4-phenylene bisacrylate) 19 and poly(ethyleneterephthalate-co-2,6-anthracenedicarboxylate) 20 can be crosslinked through the photo-cycloaddition of the unsataurated ethylene linkages. PET copolymers containing benzophenone dicarboxylate chromophores can be photocrosslinked in the solid state, most probably by the hydrogen abstraction of the benzophenone segments in the backbone upon UV irradiation.…”

Section: Introductionmentioning

confidence: 99%

Acetophenone‐assisted main‐chain photocrosslinking of poly(ethylene terephthalate)

Yun

Jang

2013

J of Applied Polymer Sci

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Maximum gel fraction of 99.1% was obtained under continuous UV irradiation of a UV energy of 200 J cm−2 on poly(ethylene terephthalate) (PET) containing only in presence of 2.9%(w/w) acetophenone (AP). The fragmented AP radicals abstract the hydrogen atoms of methylene units in PET, producing secondary methine radicals which couples to main‐chain crosslinks. The crystal structure of the crosslinked PET became disordered remarkably. The glass transition temperature disappeared and the peak thermal decomposition temperature was significantly retarded as much as 85°C. The crosslinking density and molecular weight between crosslinks reaches up to 0.129 mol g−1 and 7.7 g mol−1, respectively. Also tensile modulus and strength increased by 200 and 72% compared with those of the pristine PET respectively, resulting in more toughened PET. The solid‐state photocrosslinking may extend high‐temperature applications of PET with enhanced thermal and mechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39802.

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“…In the case of thermoplastics, where melt processing of the polymer is an important consideration, a postprocessing UV crosslinking step is an attractive approach by which to improve thermomechanical properties without sacrificing melt processability. Random copolymers of PET and the photochemically active comonomer, p ‐phenylene bisacrylate (PBA), have been synthesized by melt polymerization 5. PBA was chosen because it is difunctional and thermally stable under PET polymerization conditions; PBA can be successfully incorporated into PET using the typical melt polymerization process 5…”

Section: Introductionmentioning

confidence: 99%

“…There are few examples5, 6 in the literature of successful incorporation of such reactive comonomers in condensation polymers where polymerization is carried out at high temperatures. The resulting copolyesters undergo photochemical [2+2]‐cycloadditions upon UV irradiation.…”

Section: Introductionmentioning

confidence: 99%

“…Random copolymers of PET and the photochemically active comonomer, p-phenylene bisacrylate (PBA), have been synthesized by melt polymerization. 5 PBA was chosen because it is difunctional and thermally stable under PET polymerization conditions; PBA can be successfully incorporated into PET using the typical melt polymerization process. 5 There are few examples 5,6 in the literature of successful incorporation of such reactive comonomers in condensation polymers where polymerization is carried out at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Crosslinking studies on poly(ethylene terephthalate‐co‐1,4‐phenylene bisacrylate)

Vargas

Collard

et al. 2003

J of Applied Polymer Sci

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Several compositionally different poly(ethylene terephthalate-co-1,4-phenylene bisacrylate) (PETPBA) copolymers were melt spun into fibers. The resulting fibers were subjected to UV irradiation to induce crosslinking. Evidence of crosslinking was obtained from FTIR, solid-state 13 C-NMR, thermal analysis, and solubility. Irradiation of the fiber results in an increased glass-transition temperature, reduced thermal shrinkage, and enhanced modulus retention at elevated temperature.

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Photocrosslinkable copolyesters: Poly(alkylene terephthalate-co-1,4-phenylene bisacrylate)

Cited by 11 publications

References 28 publications

Synthesis and properties of photoalignable aromatic polyesters containing phenylenediacrylate units in their backbones and n‐alkyl moieties in their side groups

Synthesis and properties of photoalignable aromatic polyesters containing phenylenediacrylate units in their backbones and n‐alkyl moieties in their side groups

Acetophenone‐assisted main‐chain photocrosslinking of poly(ethylene terephthalate)

Crosslinking studies on poly(ethylene terephthalate‐co‐1,4‐phenylene bisacrylate)

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