Synthesis and characterization of novel borosiloxane-containing aromatic copolyimides with excellent thermal stability and low coefficient of thermal expansion

2017 ◽  
Vol 66 (8) ◽  
pp. 1173-1181 ◽  
Author(s):  
Yonglin Lei ◽  
Yuanjie Shu ◽  
Jichuan Huo
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Synthesis And Characterization ◽  
Excellent Thermal Stability

scholarly journals Thermally stable and highly efficient red-emitting Eu3+-doped Cs3GdGe3O9 phosphors for WLEDs: non-concentration quenching and negative thermal expansion

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Peipei Dang ◽  
Guogang Li ◽  
Xiaohan Yun ◽  
Qianqian Zhang ◽  
Dongjie Liu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
White Light ◽  
Coefficient Of Thermal Expansion ◽  
Internal Quantum Efficiency ◽  
Negative Thermal Expansion ◽  
Concentration Quenching ◽  
Excellent Thermal Stability ◽  
Red Phosphor ◽  
Highly Efficient

AbstractRed phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes (pc-WLEDs). However, the development of a red phosphor with simultaneous high efficiency, excellent thermal stability and high colour purity is still a challenge. In this work, unique non-concentration quenching in solid-solution Cs3Gd1 − xGe3O9:xEu3+ (CGGO:xEu3+) (x = 0.1–1.0) phosphors is successfully developed to achieve a highly efficient red-emitting Cs3EuGe3O9 (CEGO) phosphor. Under the optimal 464 nm blue light excitation, CEGO shows a strong red emission at 611 nm with a high colour purity of 95.07% and a high internal quantum efficiency of 94%. Impressively, this red-emitting CEGO phosphor exhibits a better thermal stability at higher temperatures (175–250 °C, >90%) than typical red K2SiF6:Mn4+ and Y2O3:Eu3+ phosphors, and has a remarkable volumetric negative thermal expansion (coefficient of thermal expansion, α = −5.06 × 10−5/°C, 25–250 °C). By employing this red CEGO phosphor, a fabricated pc-WLED emits warm white light with colour coordinates (0.364, 0.383), a high colour rendering index (CRI = 89.7), and a low colour coordinate temperature (CCT = 4508 K). These results indicate that this highly efficient red-emitting phosphor has great potential as a red component for pc-WLEDs, opening a new perspective for developing new phosphor materials.

scholarly journals Synthesis and characterization of carborane-containing poly(hydroxy ethers) with excellent thermal stability

2017 ◽  
Vol 35 (12) ◽  
pp. 1463-1473 ◽  
Author(s):  
Zhen Yang ◽  
Ning Li ◽  
Xiao-xue Yang ◽  
Xiao-a Zhang ◽  
Sheng-ling Jiang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Synthesis And Characterization ◽  
Excellent Thermal Stability

scholarly journals Synthesis and Characterization of Semicrystalline Polyimides Containing Bridged Linkages

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Min Chao
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
High Weight ◽  
Softening Temperature ◽  
Synthesis And Characterization ◽  
Excellent Thermal Stability

A series of polyimides (PI) containing bridged linkages were prepared successfully through a three-step technique. The results indicated that the glass transition temperature (Tg) of polyimides was affected by flexibility of polymer chain and the intermolecular interactions. ODPA-TPER-based polyimide possesses the lowest Tg, which was 214°C. All polyimides had semicrystalline characteristics, and ODPA-TPER-based PI exhibited the lowest melting temperature (Tm) at 316°C. The polyimides had high weight loss temperatures, which indicated that bridged linkages can reduce the softening temperature, meanwhile keeping excellent thermal stability.

Synthesis and Characterization of Novel Thermal Stability Poly (ester-imide-ether) with Excellent Lower Temperature Elastic Recovery

2012 ◽  
Vol 554-556 ◽  
pp. 258-262
Author(s):  
Jiao Jiao Shang ◽  
Jian Wu Lan ◽  
Shao Jian Lin ◽  
Si Chen ◽  
Ya Ni Li
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Elastic Recovery ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Melt Polymerization ◽  
Ft Ir ◽  
Lower Temperature

A new poly(ester-imide-ether) (PEIE) was prepared by melt polymerization from 1,4-butanediol(BD), polytetrahydrofuran diol (PTMG) and a novel imide dicarboxylic acid monomer which was synthesized from 3,3',4,4'-biphenyltetracarboxylic di-anhydride(BPDA) and glycine acid(GLY). The structure, thermal behaviour and elastic recovery of polymer were characterized by FT-IR. thermogravimetric analysis (TGA), differential scanning calorimetry thermograms (DSC) and laboratory stretching machine. The results showed this polymer has excellent thermal stability, 5 % weight loss temperature was at 354°C. Meanwhile, the DSC curve showed that glass-transition temperature and crystallization temperature of the polymer were at -30 °C and 160 °C, respectively. The excellent elastic recovery was still displayed at low temperature.

Solvent-resistant polyetherimide network systems via phenylethynylphthalic anhydride endcapping

1994 ◽  
Vol 6 (4) ◽  
pp. 423-435 ◽  
Author(s):  
G W Meyer ◽  
B Tan ◽  
J E McGrath
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
Compression Moulding ◽  
Network Systems ◽  
Excellent Thermal Stability ◽  
Glass Transition Temperatures ◽  
Structural Adhesives ◽  
Phenylene Diamine

The synthesis and characterization of a highly processable thermosetting polyimide system based on 22'-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride or bisphenol A dianhydride (BPA-DA) endcapped with 4-phenylethynylphthalic anhydride is described. The system afforded oligomers that were readily melt processable at high curing temperatures (380-420 CC). Imide oligomers ranging from MR = 2000 to 40 000 g molI and copolyimides were synthesized using the ester acid of the dianhydrides and either meta- and/or para-phenylene diamines as comonomers via solution imidization techniques. The oligomers were shown to display low melt viscosity values and to flow under low pressure during compression moulding. The thermally cured polymers formed tough creasable films and displayed excellent solvent resistance which was correlated to their high gel fractions (>95%). Very significant increases in glass transition temperatures were observed after cure of a 3000., oligomer. The mera-phenylene diamine-based polymer exhibited a cured Ts approximately 30C lower (233C) than the para:meta (70:30) system (267C). The all para-phenylene diamine-based homopolymers could be completely cyclized in solution but crystallized at room temperature to produce fine insoluble powders. The resulting moderately semicrystalline homopolymer showed a TM of up to 321 'C which was not observed on the second heating. These polyimides also show excellent thermal stability as judged by thermogravimetric analysis (TGA) and are being examined as structural adhesives and matrix resins.

scholarly journals Strengthening Thermal Stability in V2O5-ZnO-BaO-B2O3-M(PO3)n Glass System (M = Al, Mg) for Laser Sealing Applications

2021 ◽  
Vol 11 (10) ◽  
pp. 4603
Author(s):  
Soyoung Kim ◽  
Karam Han ◽  
Seonhoon Kim ◽  
Linganna Kadathala ◽  
Jinhyeok Kim ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Bond Strength ◽  
Coefficient Of Thermal Expansion ◽  
Glass Frit ◽  
Glass System ◽  
Fiber Types ◽  
Hermetic Sealing ◽  
Doped Glasses ◽  
Glass Panels

Today, the most common way of laser sealing is using a glass frit paste and screen printer. Laser sealing using glass frit paste has some problems, such as pores, nonuniform height, imperfect hermetic sealing, etc. In order to overcome these problems, sealing using fiber types of sealant is attractive for packaging devices. In this work, (70-x)V2O5-5ZnO-22BaO-3B2O3-xM(PO3)n glasses (mol%) incorporated with xM(PO3)n concentration (where M = Mg, Al, n = 2, 3, respectively) were fabricated and their thermal, thermomechanical, and structural properties were investigated. Most importantly, for this type of sealing, the glass should have a thermal stability (ΔT) of ≥80 °C and the coefficient of thermal expansion (CTE) between the glass and panel should be 1.0 ppm/°C. The highest thermal stability ΔT of the order of 93.2 °C and 112.9 °C was obtained for the 15 mol% of Mg(PO3)2 and Al(PO3)3 doped glasses, respectively. This reveals that the bond strength and connectivity is more strongly improved by trivalent Al(PO3)3. The CTE of a (70-x)V2O5-5ZnO-22BaO-3B2O3-xAl(PO3)3 glass system (mol%) (where x = 5–15, mol%) is in the range of 9.5–15.5 (×10−6/K), which is comparable with the CTE (9–10 (×10−6/K)) of commercial DSSC glass panels. Based on the results, the studied glass systems are considered to be suitable for laser sealing using fiber types of sealant.

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