• Bulletin of the Korean Chemical Society
• /
• 제28권12호
• /
• pp.2419-2425
• /
• 2007

New poly(cyclopenta[def]phenanthrene) (PCPP)-based conjugated copolymers, containing carbazole units as pendants, were prepared as the electroluminescent (EL) layer in light-emitting diodes (LEDs) to show that most of them have higher maximum brightness and EL efficiency. The prepared polymers, Poly(2,6-(4-(6-(Ncarbazolyl)- hexyl)-4-octyl-4H-cyclopenta[def]phenanthrene)) (CzPCPP10) and Poly(2,6-(4-(6-(N-carbazolyl)- hexyl)-4-octyl-4H-cyclopenta[def]phenanthrene))-co-(2,6-(4,4-dioctyl-4H-cyclopenta[def]phenanthrene)) (CzPCPP7 and CzPCPP5), were soluble in common organic solvents and used as the EL layer in light-emitting diodes (LEDs) of configuration with ITO/PEDOT/polymer/Ca/Al device. The polymers are thermally stable with glass transition temperature (Tg) at 77-100 °C and decomposition temperature (Td) at 423-457 °C. The studies of cyclic voltammetry indicated same HOME levels in all polymers, although the ratios of carbazole units are different. In case of PLEDs with configuration of ITO/PEDOT/CzPCPPs/Ca/Al device, The EL maximum peaks were around 450 nm, which the turn-on voltages were about 6.0-6.5 V. The maximum luminescence of PLEDs using CzPCPP10 was over 4400 cd/m2 at 6.5 V, which all of the maximum EL efficiency were 0.12 cd/A. The CIE coordinates of the EL spectrum of PLEDs using CzPCPP10 was (0.18, 0.08), which are quite close to that of the standard blue (0.14, 0.08) of NTSC.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2003년도 가을 학술발표회 논문집
• /
• pp.161-162
• /
• 2003

The synthesis and properties of aromatic polyesters have been extensively studied recently following the observation of the excellent physical and mechanical properties of thermotropic aromatic polyesters noted in both academia and industry$\^$1∼3/. Most aromatic polyesters are composed entirely of rigid, linear, aromatic ester units and as a result, they have high melting temperatures. (omitted)

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.588-591
• /
• 2004

Polyazomethine type conjugated copolymers containing phenanthridine units, poly(PZ-PTI), were synthesized by Schiff-base reaction. This new conjugated copolymer exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as phenanthridine groups. Double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) light emitting diode (LED) exhibited enhanced EL emission and efficiency compared to that of single layer (ITO/poly(PZ-PTI)/Mg) LED. With increasing the thickness of $Alq_3$ layer in double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) LED the emission peak gradually shifted to the single layer (ITO/$Alq_3$/Mg) LED, confirming good hole transporting behaviour of the synthesized conjugated copolymer.

• Elastomers and Composites
• /
• 제54권4호
• /
• pp.321-329
• /
• 2019

A series of poly(hyroxyamide)s (PHAs) was prepared by direct polycondensation reaction of 4,4'-(2,3-pyridinedioxy)dibenzoic acid and/or isophthalic acid with 3,3'-dihydroxybenzidine. The yield percentages of the products were high, and the inherent viscosities of the polymer in DMAc solution at 35℃ were 0.31-0.59 dL/g. All PHA polymers were found to be soluble in polar aprotic solvents such as DMAc, DMSO, NMP, and DMF. On the other hand, LiCl was required to dissolve IPHA-1 in aprotic solvents. Poly(benzoxazole)s (PBOs) were partially soluble in conc-H₂SO₄; IPBO-4, -5, and -6 were partially soluble in NMP only when LiCl was added to the solution, and the solution was heated. The PBO polymers showed a maximum weight loss in the temperature range of 654-680℃, and the char yields at 900℃ under nitrogen atmosphere exceeded 63%.

• Bulletin of the Korean Chemical Society
• /
• 제32권9호
• /
• pp.3306-3310
• /
• 2011

A series of novel linear aromatic ether ketone polymers containing triazole units were synthesized by click chemistry and their structures and properties were characterized by FT-IR, $^1H$ NMR, GPC, TGA, DSC and WAXD. The results showed that these polymers exhibited relatively small molecular weights distributions, good thermal stability and solvent-repelling which could have potential applications as engineering thermoplastic.

• Korea-Australia Rheology Journal
• /
• 제11권3호
• /
• pp.219-223
• /
• 1999

The effects of the transreactions on the rheological properties have been found in the poly(ethylene 2, 6-naphthalate) (PEN) and poly (ethylene terephthalate) (PET) blends. The rheological properties were very much dependent on the blend compositions, which, in turn, were related to extent of the reactions. In particular, a blend with 50/50 wt% composition exhibits an unusual and remarkable decrease in complex viscosity and it may be related to the randomness of the copolymer structure through transreactions. It has been identified by investigating the extent of transreactions and block length of the copolymer from the (ethylene 2, 6-naphthalate) (EN) and (ethylene terephthalate) (ET) units from $^1{H}$ n.m.r. spectra.

• Journal of Microbiology
• /
• 제35권2호
• /
• pp.127-133
• /
• 1997

Biosynthesis of polyhydroxybutyrate and copolymer consisting of 3-hydroxybutyrate and 3-hydroxyvalerate [poly(3HB-co-3HV)] by Bacillus thuringiensis R-510 grown with glucose or with mixtures of glucose and propionate was investigated. n-Alkanoic acids other than propionate were not precursors of 3HV units. The fraction of 3HV unit in the copolymer increased from 0 to 84 mol% of 3HV. Polymer yield decreased as the fraction of propionate was increased but the molecular weight distribution was not affected by the composition of carbon substrate. The minimum melting temperature (around 65.deg.C) of poly (3HB-co-3HV) copolymers was observed for the polymer bearing approximately 35 mol% of 3HV. Polyhydroxyalkanoates production by this organism was not dependent on nutritional limitation, but remarkably influenced by dissolved oxygen concentration in the culture medium. Low level of dissolved oxygen concentration prevented spore formation in the cells and stimulated the synthesis of polyhydroxyalkanoate. The composition of poly (3HB-co-3HV) produced by B. thuringiensis R-510 lyhydroxyalkanoate. The composition of poly(3HB-co-3HV) propduced by B. thuringiensis R-510 varied according to the growth time. However, there was no evidence that polymers isolated from cells were mixtures of immiscible polymers.

• 공업화학
• /
• 제3권1호
• /
• pp.179-187
• /
• 1992

Poly(styrene-co-maleic anhydride), SMA를 DMF 용매에 약 10%(w/w) 용액으로 한 다음 aniline, p-toluidine 및 p-chloroaniline 등으로 maleic anhydride 반복 단위를 imide화 하였다. 이미드화에 있어서 환화 탈수제(cyclodehydration agents)를 사용하였으며 최적 반응조건은 다음과 같았다. (a) 반응온도 : $80^{\circ}C$ (b) 환화 탈수제의 몰비 : SMA내 anhydride/acetic anhydride/sodium acetate/triethyl amino = 1.0/2.0/0.2/1.1. 생성된 imide-modified SMA (SMI) 시료들은 이미드화도가 증가됨에 따라 $T_g$가 증가하였으나 그 변화 정도는 크지 않았다. SMI의 $T_g$는 이미드화에 사용된 아민의 종류에 따라 aniline < p-toluidine < p-chloroaniline의 순으로 $T_g$가 증가하였다.

• 폴리머
• /
• 제24권1호
• /
• pp.58-64
• /
• 2000

폴리부틸렌테레프탈레이트 (poly(butylene terephthalate), PBT)와 파라아세톡시벤조산 (p-acetoxybenzoic acid, ABA)의 조성비를 4/6, 5/5, 6/4로 하고, 온도를 각각 250, 260, 27$0^{\circ}C$로 하여 용융 에스테르 교환반응시킴으로써 poly(butylene terephthalate-co-oxybenzoate) (PBOT)를 합성하였다. 이에 대한 양성자 핵자기 공명 분광($^1$H FT-NMR) 분석을 통해서 분자내 서열 분석을 해본 결과 연속된 oxybenzoate 단위의 수는 1.2에서 1.5사이의 값을 가졌다. 이 값은 같은 조성비 및 같은 반응온도에서 합성된 폴리에틸렌테레프탈레이트(poly(ethylene terephthalate), PET)/ABA (PEOT)쌍에 비해 상대적으로 큰 값임을 알 수 있었다. 이와 같은 블록길 이상의 차이는 열분해 거동에 영향을 미치며 그 결과 폴리옥시벤조에이트(POB), PBT 및 PEOT가 1단계의 열분해를 하는 반면 PBOT는 2단계의 열분해 거동을 나타내었다. 또한 PBOT는 PBT-rich 상, PBT와 ABA의 랜덤분포 상 및 ABA-rich 상의 3상 구조를 가지는 것으로 추측되었다.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
• /
• pp.94-94
• /
• 2003

Cross-linked polystyrene (PS) particles with carboxyl and/or poly(ethylene glycol) units on surface were formed by an emulsifier-free emulsion polymerization using styrene, methacrylic acid (MA), and poly(ethylene glycol) dimethacrylate (PEG-diMMA) at pH 7, and followed by freeze-drying to give the corresponding powders. Monodisperse polymer particles could be obtained at a concentration of PEG-diMMA 1 mol% relative to styrene. Zeta potential of polymer surface was measured to be 91 mV at a polymer of PEG-diMMA 1 mol% and was dropped as the content of MA increased.