Study on thermal properties of polyurethane-urea elastomers prepared with different dianiline chain extenders

2013 ◽  
Vol 33 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Majid Barikani ◽  
Naghmeh Fazeli ◽  
Mehdi Barikani
Keyword(s):  
Thermal Properties ◽  
Chain Extender ◽  
Polymerization Reaction ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Polymer Characterization ◽  
Cast Films ◽  
Mechanical Measurements ◽  
Chain Extenders ◽  
Thermal Stability Of

Abstract A number of polyurethane prepolymers based on polycaprolactone diol (PCL) and 4,4′-diphenyl methane diisocyanate (MDI) were synthesized and extended with different dianilines such as: 4,4′-methylenebis(2,6-diisopropylaniline) (M-DIPA), 4,4′-methylenebis(2,6diethylaniline) (M-DEA), 4,4′-methylenebis(ortho chloroaniline) (MOCA), 4,4′-methylenebis(2-isopropyl-6-methylaniline) (M-MIPA) and 4,4′-methylenebis(3-chloro-2,6-diethylaniline) (M-CDEA). Infrared (IR) spectroscopy was used to check the end of the polymerization reaction in addition to the polymer characterization. The effect of the dianiline structure on the thermal properties of the cast films were studied through dynamic mechanical measurements (DMTA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. It was found that the thermal properties and thermal stability of polyurethane are strongly affected by the molecular structure of the dianiline chain extender.

scholarly journals Thermal stability of segmented polyurethane elastomers reinforced by clay particles

2009 ◽  
Vol 63 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Jelena Pavlicevic ◽  
Jaroslava Budinski-Simendic ◽  
Mészáros Szécsényi ◽  
Nada Lazic ◽  
Milena Spirkova ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Chain Extender ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Polyurethane Elastomers ◽  
Oh Groups ◽  
Clay Nanoparticles ◽  
Thermal Stability Of

The aim of this work was to determine the influence of clay nanoparticles on thermal properties of segmented polyurethanes based on hexamethylene- diisocyanate, aliphatic polycarbonate diol and 1,4-butanediol as chain extender. The organically modified particles of montmorillonite and bentonite were used as reinforcing fillers. The structure of elastomeric materials was varied either by diol type or chain extender content. The ratio of OH groups from diol and chain extender (R) was either 1 or 10. Thermal properties of prepared materials were determined using modulated differential scanning calorimetry (MDSC). Thermal stability of obtained elastomers has been studied by simultaneously thermogravimetry coupled with DSC. The glass transition temperature, Tg, of soft segments for all investigated samples was about -33?C. On the basis of DTG results, it was concluded that obtained materials were very stable up to 300?C.

A study on the fracture, mechanical and thermal properties of chain extended recycled poly(ethylene terephthalate)

2015 ◽  
Vol 30 (8) ◽  
pp. 1157-1172 ◽  
Author(s):  
Nevin Gamze Karsli
Keyword(s):  
Thermal Properties ◽  
Ethylene Terephthalate ◽  
Chain Extender ◽  
Mechanical And Thermal Properties ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Impact Modifier ◽  
Poly Ethylene

The aim of this study is to simultaneously improve the mechanical strength and fracture toughness properties of recycled poly(ethylene terephthalate) (r-PET). For this purpose, Joncryl® was used as chain extender and Lotader® was used as impact modifier. The combined effect of chain extender and impact modifier on the chemical, fractural, mechanical, and thermal properties of r-PET was investigated. Fourier transformed infrared spectroscopy (FTIR) analysis, EWF analysis, tensile test, and differential scanning calorimetry (DSC) analysis were performed. FTIR analysis revealed that all the epoxy groups in the Joncryl® were consumed during the compounding. EWF results showed that while toughness of r-PET decreased with the addition of Joncryl®, toughness was increased with addition of impact modifier Lotader®. It was found that 2.5% Lotader® usage at the same time with Joncryl® increased the tensile strength of r-PET as well as toughness. It was observed from DSC analysis that chain extender and impact modifier addition did not change the thermal transition temperatures of r-PET.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

Epoxy Cured with Anhydride Terminated Polydimethylsiloxane: Cure Kinetics and Thermal Properties

2011 ◽  
Vol 415-417 ◽  
pp. 261-264
Author(s):  
Yuan Ren ◽  
Zheng Xi ◽  
Wen Jun Gan ◽  
Liang Zhang ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Succinic Anhydride ◽  
Cure Kinetics ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Thermogravimetric Analyses ◽  
Isothermal Measurements ◽  
Thermal Stability Of

A siloxane-containing dianhydride, succinic anhydride terminated polydimethylsiloxane (DMS-Z21) was selected to cure diglycidyl ether of bisphenol-A based epoxy resin (DGEBA). The cure kinetics and thermal properties were investigated by nonisothermal and isothermal differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA), respectively. The activation energy (Ea) of the curing reaction was obtained based on the methods of Kissinger and isothermal measurements. The results of the thermogravimetric analyses of the DGEBA/DMS-Z21 system showed that the thermal stability of the DGEBA/DMS-Z21 system was slightly higher than the DGEBA/MeTHPA system.

Preparation and Characterization of Blended Composite Membranes

2012 ◽  
Vol 488-489 ◽  
pp. 506-510 ◽  
Author(s):  
Sikander Rafiq ◽  
Zakaria Man ◽  
Abdulhalim Maulud ◽  
Nawshad Muhammad ◽  
Saikat Maitra
Keyword(s):  
Spectroscopic Analysis ◽  
Sol Gel ◽  
Composite Membranes ◽  
Hybrid Membranes ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Thermal Stability Of ◽  
Scanning Electron

Composite membranes were prepared by incorporating inorganic silica nanoparticles into blends of polysulfone/polyimide (PSF/PI) membranes via sol-gel route. Morphological structures of the developed membranes were carried out by scanning electron microscopy (SEM). Spectroscopic analysis of the hybrid membranes were done by fourier transform infrared spectroscopy (FTIR) analysis. Differential scanning calorimetry (DSC) analysis shows that the glass transition temperature (Tg) increased from 209oC to 238oC in the hybrid membranes followed by thermogravimetric analysis (TGA) that showed significant improvement in thermal stability of the developed membranes.

scholarly journals Thermal properties of flax fiber scoured by different methods

2015 ◽  
Vol 19 (3) ◽  
pp. 939-945 ◽  
Author(s):  
Dong Zheng ◽  
Ruo-Yao Ding ◽  
Zheng Lei ◽  
Zhang Xingqun ◽  
Yu Chong-Wen
Keyword(s):  
Thermal Properties ◽  
Thermal Behavior ◽  
Value Added ◽  
Exothermic Peak ◽  
Endothermic Peak ◽  
Scanning Calorimetry ◽  
Volatile Products ◽  
Third Stage ◽  
Thermal Stability Of ◽  
Thermal Gravity Analyzer

Thermal properties of flax roves untreated and treated were characterized by differential scanning calorimetry (DSC) and thermal gravity analyzer (TGA) in order to understand their thermal behavior in more detail and to evaluate the effect of scouring processing on the thermal behavior. Flax roves were treated with six kinds of methods including biological scouring, one bath, two bath, bleaching, alkali scouring and industry chemical scouring as standards. Results showed that all treatments improved thermal stability of flax roves. The results indicated that glass transition temperature (Tg) decreased after scouring besides the sample by directly bleaching. It is more difficult to determine the endothermic peak of flax treated by chemical scouring in industry because it takes a very flat course. A distinct endothermic peak was observed for the untreated flax rove, while a distinct exothermic peak in different temperature interval was revealed for other four treated flax rove samples. For TGA analysis, thermal degradation of flax roves studied consists of three regions of the initial, main, and char decomposition, and the third stage consists of secondary weight loss and carbonization for flax roves with biological scouring, one-bath and two-bath. Besides, different residue left indicates that the bio-scoured flax roves are lost with volatile products and does not contribute to char formation. These results provide valuable preferences for mechanism and top value added application of bio-scouring in flax roves.

scholarly journals Antistatic and Thermal Properties of Poly(Lactic Acid)/Polypropylene/Carbon Nanotube Nanocomposites

2020 ◽  
Vol 16 (2) ◽  
pp. 57-69
Author(s):  
Wen Shyang Chow ◽  
Yuan Ting Lim
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Poly Lactic Acid ◽  
Compression Moulding ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Crystallisation Temperature ◽  
Pp Blends ◽  
Thermal Stability Of

The aim of this study is to investigate the influence of carbon nanotubes (CNT) on the antistatic and thermal properties of poly(lactic acid)/polypropylene/carbon nanotubes (PLA/PP/CNT) nanocomposites. PLA/PP (blend ratio = 60:40) containing CNT (loading 1.0 to 2.5 phr) was melt-compounded followed by compression moulding. The antistatic properties of PLA/PP/CNT nanocomposites achieved at 2.5 phr CNT loading. Thermogravimetric analysis (TGA) results indicated that the thermal stability of PLA/PP/ CNT nanocomposite was higher than PLA/PP blend. Differential Scanning Calorimetry (DSC) results demonstrated that CNT reduced the cold crystallisation temperature of PLA, while increased the crystallisation temperature of PP, which evidenced the nucleatingability of CNT in the PLA/PP blends.

scholarly journals New Waterborne Polyurethane-Urea Synthesized with Ether-Carbonate Copolymer and Amino-Alcohol Chain Extenders with Tailored Pressure-Sensitive Adhesion Properties

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 627 ◽  
Author(s):  
Mónica Fuensanta ◽  
Abbas Khoshnood ◽  
Francisco Rodríguez-Llansola ◽  
José Miguel Martín-Martínez
Keyword(s):  
Amino Alcohol ◽  
Peel Test ◽  
Waterborne Polyurethane ◽  
Chain Extender ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Adhesion Properties ◽  
Oh Groups ◽  
Pressure Sensitive ◽  
Chain Extenders

New waterborne polyurethane-urea dispersions with adequate adhesion and cohesion properties have been synthesized by reacting isophorone diisocyanate, copolymer of ether and carbonate diol polyol and three amino-alcohols with different number of OH groups chain extenders using the prepolymer method. The waterborne polyurethane-urea dispersions were characterized by pH, particle-size distribution, and viscosity, and the polyurethane-urea films were characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and plate-plate rheology (temperature and frequency sweeps). Polyurethane-urea pressure-sensitive adhesives (PUU PSAs) were prepared by placing the waterborne polyurethane dispersions on polyethylene terephthalate (PET) films and they were characterized at 25 °C by creep test, tack and 180° peel test. The waterborne polyurethane-urea dispersions showed mean particle sizes between 51 and 78 nm and viscosities in the range of 58–133 mPa·s. The polyurethane-urea films showed glass transition temperatures (Tgs) lower than −64 °C, and they showed a cross of the storage and loss moduli between −8 and 68 °C depending on the number of OH groups in the amino-alcohol chain extender. Different types of PUU PSAs (removable, high shear) were obtained by changing the number of OH groups in the amino-alcohol chain extender. The tack at 25 °C of the PUU PSAs varied between 488 and 1807 kPa and the 180° peel strength values ranged between 0.4 and 6.4 N/cm, and their holding times were between 2 min and 5 days. The new PUU PSAs made with amino-alcohol chain extender seemed very promising for designing environmentally friendly waterborne PSAs with high tack and improved cohesion and adhesion property.

scholarly journals Thermal Stability of Wood Fibers Produced from Recycled Medium Density Fiberboards

2019 ◽  
Vol 70 (2) ◽  
pp. 149-155
Author(s):  
Mohammad Ahmadi ◽  
Bita Moezzipour ◽  
Aida Moezzipour
Keyword(s):  
Thermal Stability ◽  
Chemical Structure ◽  
Electrical Heating ◽  
Wood Fibers ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Thermal Deterioration ◽  
Recycled Fibers ◽  
Thermal Stability Of

In this study, thermal stability of fibers obtained from recycled MDF was investigated and compared with virgin fibers by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Two different methods, including electrical heating and hydrothermal treatment, were used for recycling the MDF wastes. Electrical heating method was performed at two different times (2 and 4 min) and hydrothermal method was done at three different temperatures (105, 125 and 150 °C). Chemical structure of wood fibers was also studied. TGA and DSC analysis showed higher weight loss of recycled fibers as compared to virgin fibers in a similar degradation region, which means that thermal stability of recycled fibers is lower than virgin fibers. In fact, thermal behavior of recycled fibers was medium between wood and UF resin. DSC analysis showed two exotherms at around 340 and 475 °C. The transition at around 340 °C in fibers thermogram was considered to be due to polysaccharides thermal deterioration and the exotherm at 475 °C was related to lignin carbohydrate complex deterioration. The results of chemical structure analysis showed that lignin and hemicellulose content of recycled fibers was significantly lower than that of virgin fibers, which resulted in decreased thermal stability.

A fabrication and characterization of luffa/PANI/PEO biocomposite nanofibers by means of electrospinning

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gözde Konuk Ege ◽  
Hüseyin Yüce ◽  
Özge Akay ◽  
Hasbi Öner ◽  
Garip Genç
Keyword(s):  
Thermal Properties ◽  
Alkali Treatment ◽  
Natural Fibers ◽  
Weight Ratio ◽  
Morphological Structure ◽  
Film Structure ◽  
Morphological Properties ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Content Type

Purpose This paper aims to address the production of biocomposite nanofibers using luffa natural fibers and polyaniline conductive polymer/polyethylene oxides (PANI/PEO). Design/methodology/approach In this study, luffa natural fibers are extracted by chemical method. After mixing the treated luffa (TL) with the PANI/PEO solution, TL/PANI/PEO nanofibers were produced by electrospinning (ES) method under different ES parameters to examine the optimal conditions for nanofiber production. Then TL/PANI/PEO biocomposite nanofibers prepared in different weight ratios were produced to analyze the effects of luffa in the morphology and thermal properties of the biocomposite nanofibers. The characterization analysis of TL/PANI/PEO biocomposite nanofibers was performed by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis methods. Findings The analysis shows that different weight ratios of TL to PANI/PEO changed the morphology of the membrane. When increasing the weight ratio of TL, the morphological structure of TL/PANI/PEO transformed from nanofiber structure to thin film structure. The appearance of O—H peaks in the FTIR results proved the existence of TL in PANI/PEO nanofibers (membrane). Moreover, an increase in the weight ratio of luffa from 2% to 7.5% leads to an increase in the peak intensity of the O—H group. Regarding DSC analysis, biocomposite nanofibers improved the thermal properties. According to all results, 2%wt TL/PANI/PEO showed optimal morphological properties. Originality/value Plant cellulose was extracted from the luffa, one of the natural fibers, by method of alkali treatment. A new type of biocomposite nanofibers was produced using TL blend with PANI via electrospinning method.

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