Comparative study of transparent polyimides derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine

2016 ◽  
Vol 29 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Yu Zhou ◽  
Guofei Chen ◽  
Wei Wang ◽  
Liping Song ◽  
Xingzhong Fang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Glass Transition ◽  
Comparative Study ◽  
Step Method ◽  
Glass Transition Temperatures ◽  
Step Procedure ◽  
One Step ◽  
Solution Polycondensation

Two series of polyimides (PIs) derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine were synthesized via solution polycondensation. The poly(ether imide)s could be formed by the conventional one-step method, while the poly(ester imide)s were only afforded by the two-step procedure. The resulting PIs had glass transition temperatures ( Tgs) in the range of 224–320°C and exhibited good mechanical properties with tensile strength in the range of 80.5–96.5 MPa, tensile moduli 2.7–6.9 GPa, and elongations at break 1.5–17.3%. It was found that the PIs derived from bis(ether anhydride)s showed higher thermal stability, better solubility, and transparency but lower Tg and higher water absorption compared with bis(ester anhydride)-based PIs due to the different ether and ester linkages.

Highly Soluble and Transparent of Novel Polyimides Containing Trifluoromethyl and Cyclohexane Units

2011 ◽  
Vol 332-334 ◽  
pp. 1918-1921
Author(s):  
Xin Mo ◽  
Guang Li ◽  
Jian Ming Jiang
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Glass Transition ◽  
Transition Temperature ◽  
Moisture Absorption ◽  
Electronic Materials ◽  
Step Method ◽  
Polar Solvents ◽  
Methyl Cyclohexane ◽  
One Step

Two novel polyimides(PIs) were polymerized from 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane, with aromatic tetracarboxylic dianhydrides using the typical one-step method. The inherent viscosity of the PIs were around 0.90dL/g, and they exhibited an excellent solubility and optical property. They were readily soluble not only in some strong polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), but also in some low-boiling-point solvents such as chloroform (CDCl3), and tetrahydrofuran (THF). The PIs film showed high optical transparency and colorless with cut-off wavelength in 332nm and 338nm. Meanwhile, the temperature of 10% weight loss in air and nitrogen were higher than 441°C and 449°C respectively, and their glass-transition temperature (Tg) were higher than 348 °C. Furthermore, they possessed good mechanical properties with tensile strengths of 69–71MPa, elongations at break of 11.6–15.4% and low moisture absorption (<2%).Due to their properties, the polyimides could be considered as photoelectric and micro-electronic materials.

The Research of Poly Propylene Carbonate /Nano-SiO2 Composites

2014 ◽  
Vol 904 ◽  
pp. 74-77 ◽  
Author(s):  
Qu Li ◽  
Heng Wu ◽  
Si Yuan Xie ◽  
Jiao Sun ◽  
Xing Hai Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Propylene Carbonate ◽  
Tensile Tests ◽  
Slight Improvement ◽  
Biodegradable Poly ◽  
Poly Propylene

Biodegradable poly (propylene carbonate) (PPC) composite with a slight improvement in the thermal stability and tensile strength was successfully prepared by incorporating a low content of nano-SiO2. Tensile tests demonstrate the better mechanical properties of the composites prepared in this study. The obtained composites increases sharply from 1.57Mpa to 12.04Mpa by incorporating 5wt% nano-SiO2. Furthermore, the composites show approximately 8°C higher glass transition temperature (Tg) than that of neat PPC.The Tdmax of composite with 5wt% of nano-SiO2 was about 40°C higher than that of neat PPC.

scholarly journals Determination of Thermo-Mechanical Properties of Recycled Polyurethane From Glycolysis Polyol

2021 ◽  
Vol 11 (4) ◽  
pp. 75-87
Author(s):  
James Njuguna ◽  
Peter Muchiri ◽  
Nancy Karuri ◽  
Fredrick Madaraka Mwema ◽  
Michael T. Herzog ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Hardness Test ◽  
Raw Material ◽  
Glass Transition Temperatures ◽  
D Values

This study aimed to determine the possible changes in thermo-mechanical properties between recycled polyurethane with benchmark polyurethane. The glycolysis polyol was used as a raw material for recycled polyurethane production. The glass transition temperature of the recycled polyurethane was determined using DSC. Tensile strength, elastic modulus, toughness, and hardness test of the recycled polyurethane were conducted at 24°C, 40°C, and 60°C. The glass transition temperatures for the recycled and the benchmark polyurethane occurred at 43°C and 50.4°C, respectively. Tensile strength for recycled polyurethane was lower than that of benchmark polyurethane by 29-43%. Recycled polyurethane recorded lower toughness than petroleum-based pure polyurethane by 13-16%. However, recycled polyurethane recorded high shored D values than the benchmark polyurethane by 9-29%. This study reveals that recycled polyol could be used as feedstock for polyurethane production with applications tailored to its mechanical properties.

Heterocyclic polyamides with pendent imide groups

1995 ◽  
Vol 7 (4) ◽  
pp. 451-459 ◽  
Author(s):  
C Hamciuc ◽  
E Hamciuc ◽  
M Bruma ◽  
A Stoleriu ◽  
I Diaconu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Glass Transition ◽  
Low Temperature ◽  
Dielectric Constants ◽  
Inherent Viscosity ◽  
Aromatic Acids ◽  
Temperature Solution ◽  
Solution Polycondensation

New poly(phenylquinoxaline-amide)s and poly(phenylquinoxaline-imide-amide)s containing pendent phthalimide or 3,4,5,6-tctrachlorphthalimide groups have been synthesized by low-temperature solution polycondensation of diaminophenylquinoxalines with diacid chlorides of two aromatic acids containing preformed imide ridgs. The inherent viscosity, solubility, thermal stability, glass transition tempratures, dielectric constants and mechanical properties of these polymers have been studied.

Organosoluble and transparent cardo polyimides with high Tg derived from 9,9-bis(4-aminophenyl)xanthene

2018 ◽  
Vol 31 (8) ◽  
pp. 909-918 ◽  
Author(s):  
Xiao-Lan Zhang ◽  
Cheng Song ◽  
Mei-Hong Wei ◽  
Zhen-Zhong Huang ◽  
Shou-Ri Sheng
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Glass Transition ◽  
Amic Acid ◽  
Dielectric Constants ◽  
Cutoff Wavelength ◽  
One Pot ◽  
Glass Transition Temperatures ◽  
Good Thermal Stability ◽  
Step Procedure

9,9-Bis(4-aminophenyl)xanthene (BAPX) was prepared simply and effectively via one-pot, two-step procedure using xanthenone and aniline as main substrates. The monomer BAPX was reacted with six aromatic dianhydrides in N, N-dimethylacetamide (DMAc) to yield the corresponding polyimides (PIs) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The resulting PIs exhibited good thermal stability with glass transition temperatures of 308–348°C, initial decomposition temperatures of 470–510°C, 10% weight loss temperatures of 540–565°C, and char yields of 55–59% at 800°C in nitrogen, respectively. All polymers were amorphous and readily soluble in organic solvents such as N-methyl-2-pyrrolidone and DMAc. The PI films had tensile strengths of 71–92 MPa, tensile moduli of 1.91–2.35 GPa, and elongations at break of 5–13%. Meanwhile, these polymer films also had high optical transparency with a cutoff wavelength in the range of 367–415 nm, lower dielectric constants (3.02–3.34 at 10 MHz), and low water uptake of 0.30–0.52%.

The Effect of the Vulcanizing System on Cure and Mechanical Properties of Nbr/Epdm Blends

2001 ◽  
Vol 9 (7) ◽  
pp. 459-468 ◽  
Author(s):  
Marcia G. Oliveira ◽  
Bluma G. Soares
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Glass Transition ◽  
Crosslink Density ◽  
Mechanical Performance ◽  
The Other ◽  
Glass Transition Temperatures ◽  
Sulphur Concentration ◽  
Curing Characteristics ◽  
Accelerator System

The effect of the curing system and curing parameters, mechanical properties, ageing resistance, and crosslink density of NBR/EPDM blends has been investigated. The curing characteristics of the blends were affected by the accelerator type and the sulphur concentration. The sulphur/benzothiazyl-disulphide (S/MBTS) vulcanizing system offered the best scorch safety, whereas those single and binary accelerator systems based on tetramethyl thiuram disulphide (TMTD) provided faster cure. The MBTS single accelerator system was able to crosslink the EPDM phase better and consequently displayed better mechanical performance than the other systems based on tetramethyl thiuram disulphide (TMTD). Higher thermal stability was also achieved in blends containing higher levels of sulphur, probably because of increased crosslinking in the EPDM phase. The results of dynamic mechanical investigations showed differences in the glass transition temperatures, which increased with increasing of the sulphur content in both S/MBTS and S/MBTS/TMTD vulcanizing systems. Formulations based on S/TMTD single accelerator systems gave the lowest values of Tg, and the amount of sulphur did not affect this property.

Synthesis and properties of transparent polyimides derived from 1,4-cyclohexylene bis(trimellitate anhydride)

2017 ◽  
Vol 29 (6) ◽  
pp. 627-635 ◽  
Author(s):  
Guofei Chen ◽  
Yu Zhou ◽  
Kai Ma ◽  
Wei Wang ◽  
Xingzhong Fang
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Optical Transparency ◽  
Transition Temperatures ◽  
Step Method ◽  
Glass Transition Temperatures

A series of polyimides (PIs) derived from 1,4-cyclohexylene bis(trimellitate anhydride) (TACH) was synthesized by conventional two-step method with chemical imidization. The resulting PIs had glass transition temperatures ( Tgs) in the range of 188–240°C and exhibited good mechanical properties with tensile strengths of 50.0–90.2 MPa, tensile moduli of 2.2–3.9 GPa, and elongations at break of 2.9–5.8%. These PI films showed high optical transparency with cut-off wavelengths of 345–369 nm and high transmittance at 500 nm with more than 84%. Compared with PIs derived from 1,4-bis(3,4-dicarboxyphenoxy)cyclohexane dianhydride, the TACH-based PIs showed higher Tg, better solubility, and competitive transparency.

Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Shear Modulus ◽  
High Impact ◽  
Necessary Condition ◽  
Step Method ◽  
Melt Mixing ◽  
One Step ◽  
High Impact Strength ◽  
Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

Discussion on Repair Method of Concrete Highway Pavement

2013 ◽  
Vol 321-324 ◽  
pp. 209-212
Author(s):  
Chun Yan Xia
Keyword(s):  
Mechanical Properties ◽  
Preparation Program ◽  
Step Method ◽  
Concrete Technology ◽  
Concrete Material ◽  
Repair Method ◽  
Ordinary Concrete ◽  
One Step ◽  
Highway Pavement

nfluences on properties of the concrete highway pavement were analyzed in this paper, and the optimal formulation materials were gotten to use in the repair of used-broken cement blocks in the experiment. Polyurethane concrete material was prepared, combing the ordinary concrete technology with one-step method of the synthesis of polyurethane hard bubble, and then its mechanical properties of the relevant parameters were measured to determine the optimal preparation program. The results show that the polyurethane concrete also has sufficiently good mechanical properties while it has the characteristic of fast patching.

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