scholarly journals Synthesis of thermoplastic poly(ester-siloxane)s in the melt and in solution

2005 ◽  
Vol 70 (12) ◽  
pp. 1469-1485 ◽  
Author(s):  
Biljana Dojcinovic ◽  
Vesna Antic ◽  
Marija Vuckovic ◽  
Jasna Djonlagic
Keyword(s):  
1H Nmr Spectroscopy ◽  
Hard Segment ◽  
Soft Segment ◽  
Weight Ratio ◽  
Thermoplastic Elastomers ◽  
Degree Of Crystallinity ◽  
Mechanical Spectroscopy ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
High Boiling Solvent

Two series of thermoplastic elastomers, based on poly(dimethylsiloxane) PDMS, as the soft segment and poly(butylene terephthalate), PBT, as the hard segment, were synthesized by catalyzed transesterification, from dimethyl terephthalate, DMT, silanol-terminated poly(dimethylsiloxane), PDMS-OH Mn=1750g/mol, and 1,4-butanediol, BD. The mole ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 55:45. The first series was synthesized in order to determine the optimal mole ratio of BD and DMT for the synthesis of high molecular weight thermoplastic poly(ester-siloxane)s, TPESs. The second series was performed in the presence of the high-boiling solvent, 1,2,4-trichlorbenzene in order to increase the mixing between the extremely non-polar siloxane prepolymer and the polar reactants, DMT and BD, and, therefore, avoid phase separation during synthesis. The structure and composition of the synthesized poly(ester-siloxane)s were verified by 1H-NMR spectroscopy, while the melting temperatures and degree of crystallinity were determined by differential scanning calorimetry (DSC). The effectiveness of the incorporation of the silanol-terminated poly( dimethylsiloxane) into the polyester chains was verified by chloroform extraction. The rheological properties of the poly(ester-siloxane)s were investigated by dynamic mechanical spectroscopy (DMA).

scholarly journals Synthesis of thermoplastic poly(ester-olefin) elastomers

2004 ◽  
Vol 58 (10) ◽  
pp. 444-449
Author(s):  
Branka Tanasijevic ◽  
Salem Elkhaseh ◽  
Marija Nikolic ◽  
Jasna Djonlagic
Keyword(s):  
Soft Segment ◽  
Weight Ratio ◽  
Soxhlet Extraction ◽  
Thermoplastic Elastomers ◽  
Molecular Structures ◽  
Degree Of Crystallinity ◽  
Molar Ratio ◽  
Mechanical Spectroscopy ◽  
Scanning Calorimetry ◽  
High Boiling Solvent

A series of thermoplastic poly(ester-olefin) elastomers, based on poly(ethylene-stat-butylene), HO-PEB-OH, as the soft segment and poly (butylene terephthalate), PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene) segments into the copolyester backbone was accomplished by the polycondensation of ?, ?-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol) with 1,4-butanediol (BD) and dimethyl terephthalate (DMT) in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu)4), and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD), as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu)4) for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylene)s were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefin)s were investigated by differential scanning calorimetry (DSC). The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA). The rheological properties of poly(ester-olefin)s were investigated by dynamic mechanical spectroscopy in the melt and solid state.

Synthesis and Properties of Novel Multiblock Thermoplastic Elastomers - Poly(ester-imide-ether) - Based on Pyromellitic Dianhydride, Glycine, 1,4-Butanediol and Polytetramethylene Glycol

2012 ◽  
Vol 550-553 ◽  
pp. 822-826 ◽  
Author(s):  
Si Chen ◽  
Shao Jian Lin ◽  
Jian Wu Lan ◽  
Jiao Jiao Shang ◽  
Ya Ni Li ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
1H Nmr Spectroscopy ◽  
Soft Segment ◽  
Thermoplastic Elastomers ◽  
Pyromellitic Dianhydride ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Good Solubility

A series of multiblock thermoplastic ploy(ester imide ether)s elastomers derived from polytetramethylene glycol of molecule weight is 1000 (PTMG1000), 1,4-butanediol (BD), and a new imide diacid monomer were synthesized of Pyromellitic dianhydride (PMDA) and glycine (GLY). was synthesized by two-step melting polycondensation method. Their chemical structures were studied by 1H-NMR spectroscopy as well as their thermal properties of the copolymers were investigated from differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), respectively. Otherwise, the solubility of these polymers was characterized by various organic solvents. The effects of the hard/soft segment content on the thermal properties and soluble behavior were investigated. The result demonstrated that these copolymers had better thermal properties (Tm: 225~280°C and T5% : 350~353°C) than those of conventional thermoplastic elastomers due to the introduction of imide bond. At the same time, the polymers have good solubility.

scholarly journals Impact of environmental agents on non-woven polylactide/natural rubber agrofiber

2021 ◽  
Vol 285 ◽  
pp. 07034
Author(s):  
Yulia Tertyshnaya ◽  
Maksim Zakharov ◽  
Alina Ivanitskikh ◽  
Anatoliy Popov
Keyword(s):  
Natural Rubber ◽  
Uv Irradiation ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
Distilled Water ◽  
Fibrous Materials ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Environmental Agents ◽  
The Degree Of Crystallinity

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.

Magnetic Properties of Irradiated Nickel Ferrite Thermoplastic Natural Rubber Nanocomposite

2014 ◽  
Vol 879 ◽  
pp. 206-212 ◽  
Author(s):  
Sivanesan Appadu ◽  
Sahrim Hj. Ahmad ◽  
Chantara Thevy Ratnam ◽  
Meor Yahaya Razali ◽  
Moayad Husein Flaifel ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermal Properties ◽  
Natural Rubber ◽  
Weight Ratio ◽  
Xrd Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Magnetic Microstructure ◽  
Sem Image ◽  
Thermoplastic Natural Rubber

The effect of electron beam (EB) irradiation at different doses on the magnetic, microstructure, morphological and thermal properties of NiFe2O4/Thermoplastic Natural Rubber (TPNR) nanocomposite was investigated. The NiFe2O4/TPNR nanocomposite samples were prepared by using a Haake mixer in weight ratio of 12:88. The TPNR matrix consists of natural rubber (NR), liquid natural rubber (LNR) and high density polyethylene (HDPE) in weight ratio of 20:10:70. The samples were irradiated using a 2 MeV EB machine in doses from 0 - 200 kGy. Magnetic properties studied by using the vibrating sample magnetometer (VSM) at room temperature showed that the values of saturation magnetization (MS), remanence magnetization (MR) and the coercivity (HC) value increased with increasing doses of irradiation. The increase in MSand MRvalues is attributed to the increase in concentration of Fe3+ions at octahedral B-site and decrease of concentration at the tetrahedral A-site in the NiFe2O4cubic structure. X-ray diffraction (XRD) analysis of the samples showed that peak intensities decreased and the width of the peaks increased with increasing doses of irradiation. Scanning electron microscope (SEM) image of the nanocomposite cross section showed the presence of defects which is more visible with increasing doses of irradiation. In the case of thermal properties, differential scanning calorimetry (DSC) analysis showed that the crystallization temperature (Tc) and the degree of crystallinity (Xc) of the nanocomposite samples decreased with increasing doses of irradiation due to crosslinking of polymeric chains which hinders the growth of crystals.

scholarly journals Shape memory polyurethanes based on recycled polyvinyl butyral. I. Synthesis and morphology

2013 ◽  
Vol 11 (12) ◽  
pp. 2058-2065 ◽  
Author(s):  
Tsvetomir Tsonev ◽  
Michael Herzog ◽  
Sanchi Nenkova
Keyword(s):  
Shape Memory ◽  
Hard Segment ◽  
Soft Segment ◽  
Polyvinyl Butyral ◽  
Mechanical Analysis ◽  
Attenuated Total Reflection ◽  
Polypropylene Glycol ◽  
Scanning Calorimetry ◽  
Chemical Crosslinks ◽  
Physical And Chemical

AbstractShape memory polyurethanes (SMPUs) were synthesized by 4,4′-diphenylmethane diisocyanate (MDI), hexane-1,6-diol (HD), polypropylene glycol (PPG), and recycled polyvinyl butyral (PVB). Dynamic mechanical analysis, differential scanning calorimetry and Fourier transformation infrared attenuated total reflection spectroscopy was used to characterize the poly (vinylbutyral-urethanes). Micro-phase domain separation of hard and soft segments and phase inversion were investigated. Increasing the hard segment content, i.e., average hard segment molecular weight, leads to an increase in the degree of micro-phase separation, hard domain order and crystallinity. The crystalline hard segment structures combined with the elastic nature of soft segment matrix provide enough physical and chemical crosslinks to have shape memory effect.

Properties of Polyether-Polyester Thermoplastic Elastomers

1977 ◽  
Vol 50 (1) ◽  
pp. 1-23 ◽  
Author(s):  
A. Lilaonitkul ◽  
S. L. Cooper
Keyword(s):  
Melting Point ◽  
Hard Segment ◽  
Elevated Temperatures ◽  
Basic Structure ◽  
Thermoplastic Elastomers ◽  
Degree Of Crystallinity ◽  
Fabrication Procedure ◽  
Hard Segments ◽  
Average Block ◽  
Definition Of

Abstract The viscoelastic properties of polytetramethylene oxide—polytetramethylene terephthalate block polymers are strongly influenced by phase separation of the 4GT hard blocks into crystalline domains. Thermal analysis reveals a single Tg which increases with increasing 4GT content. This suggests that short sequences of hard segments form a compatible interlamellar amorphous phase with the polyether component. The Gordon-Taylor equation was found to model Tg behavior accurately, provided that the crystalline polyester component was not included in the definition of the hard segment. The melting point of the polytetramethylene terephthalate blocks depends on the average block length of crystallizable segment. Incorporating non-crystallizing polytetramethylene 1,4-cyclohexanedicarboxylate into the hard segment reduces the 4GT melting point and degree of crystallinity. The morphological features of the copolymers depend on sample composition and fabrication procedure. The basic structure is spherulitic. Three different types of spherulite were observed: positive and negative spherulites, as well as spherulites which have their optical axis 45° to their radial direction. The different spherulite types are relatively stable; annealing the samples at elevated temperatures does not alter their morphology. Annealing does increase the degree of crystallinity somewhat and produces crystallites in equilibrium at the annealing temperature. Infrared dichroism studies reveal that, at low deformations, the hard segment lamellae orient as a whole in the stretching direction. This is refleeted by the initial negative orientation of the hard segments. At this stage of elongation, the deformation of the crystallites is nearly reversible. At higher strain levels, the lamellae are disrupted and the hard segments orient positively with a high degree of orientational hysteresis. The soft segments, however, orient almost reversibly in the stress direction at all strain levels studied. It is concluded that the extensive stress softening is brought about by plastic deformation of the crystalline hard segments.

scholarly journals Investigating Physio-Thermo-Mechanical Properties of Polyurethane and Thermoplastics Nanocomposite in Various Applications

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2467
Author(s):  
Tyser Allami ◽  
Ahmed Alamiery ◽  
Mohamed H. Nassir ◽  
Amir H. Kadhum
Keyword(s):  
Thermal Stability ◽  
Electrical Properties ◽  
Hard Segment ◽  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
Tensile Modulus ◽  
Scanning Calorimetry ◽  
Strain Behavior ◽  
Phase Separation Kinetics ◽  
Thermal Stability Of

The effect of the soft and hard polyurethane (PU) segments caused by the hydrogen link in phase-separation kinetics was studied to investigate the morphological annealing of PU and thermoplastic polyurethane (TPU). The significance of the segmented PUs is to achieve enough stability for further applications in biomedical and environmental fields. In addition, other research focuses on widening the plastic features and adjusting the PU–polyimide ratio to create elastomer of the poly(urethane-imide). Regarding TPU- and PU-nanocomposite, numerous studies investigated the incorporation of inorganic nanofillers such as carbon or clay to incorporating TPU-nanocomposite in several applications. Additionally, the complete exfoliation was observed up to 5% and 3% of TPU–clay modified with 12 amino lauric acid and benzidine, respectively. PU-nanocomposite of 5 wt.% Cloisite®30B showed an increase in modulus and tensile strength by 110% and 160%, respectively. However, the nanocomposite PU-0.5 wt.% Carbone Nanotubes (CNTs) show an increase in the tensile modulus by 30% to 90% for blown and flat films, respectively. Coating PU influences stress-strain behavior because of the interaction between the soft segment and physical crosslinkers. The thermophysical properties of the TPU matrix have shown two glass transition temperatures (Tg’s) corresponding to the soft and the hard segment. Adding a small amount of tethered clay shifts Tg for both segments by 44 °C and 13 °C, respectively, while adding clay from 1 to 5 wt.% results in increasing the thermal stability of TPU composite from 12 to 34 °C, respectively. The differential scanning calorimetry (DSC) was used to investigate the phase structure of PU dispersion, showing an increase in thermal stability, solubility, and flexibility. Regarding the electrical properties, the maximum piezoresistivity (10 S/m) of 7.4 wt.% MWCNT was enhanced by 92.92%. The chemical structure of the PU–CNT composite has shown a degree of agglomeration under disruption of the sp2 carbon structure. However, with extended graphene loading to 5.7 wt.%, piezoresistivity could hit 10-1 S/m, less than 100 times that of PU. In addition to electrical properties, the acoustic behavior of MWCNT (0.35 wt.%)/SiO2 (0.2 wt.%)/PU has shown sound absorption of 80 dB compared to the PU foam sample. Other nanofillers, such as SiO2, TiO2, ZnO, Al2O3, were studied showing an improvement in the thermal stability of the polymer and enhancing scratch and abrasion resistance.

scholarly journals Synthesis, structure and properties of thermoplastic poly(ester-siloxane) elastomers

2006 ◽  
Vol 71 (7) ◽  
pp. 839-842
Author(s):  
Vesna Antic ◽  
Jasna Djonlagic
Keyword(s):  
1H Nmr Spectroscopy ◽  
Mechanical Analysis ◽  
Structure And Properties ◽  
Mass Ratio ◽  
Scanning Calorimetry ◽  
Constant Length ◽  
Melting Temperatures ◽  
Soft Segments ◽  
In Series ◽  
Hard Segments

Two series of thermoplastic poly(ester-siloxane) elastomers (TPES), with hard segments based on poly(butylene terephthalate) (PBT) and soft segments based on poly(dimethylsiloxane) (PDMS), were synthesized by high-temperature two-step transesterification reaction in the melt. In series I, the mass ratio of hard and soft segments was kept constant (57:43), while the length of the segments was varied, whereas in series II, the mass ratio of hard and soft segments was varied in range from 70:30 to 40:60, with a constant length of the soft segments. The segmented structure of the poly(ester-siloxane) copolymers was verified by 1H-NMR spectroscopy of the soluble and insoluble fractions, obtained after extraction of the samples with chloroform. The influence of the structure and composition of the TPES on the melting temperatures and degrees of crystallinity was investigated by differential scanning calorimetry (DSC). The rheological properties were investigated by dynamic mechanical analysis (DMA).

scholarly journals Functionalization of Cellulose through Polyurethanization by the Addition of Polyethylene Glycol and Diisocyanate

2019 ◽  
Vol 19 (1) ◽  
pp. 124
Author(s):  
Imam Prabowo ◽  
Ghiska Ramahdita ◽  
Mochamad Chalid
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Simultaneous Thermal Analysis ◽  
High Strength ◽  
Melting Temperatures ◽  
Grafting Technique ◽  
Plastic Materials ◽  
1H Nuclear Magnetic Resonance ◽  
A Chain ◽  
The Impact

Plastic consumption becomes a main factor of land pollution due to poor degradability. To reduce the impact of land pollution, a biodegradable material such as cellulose, which has biodegradability, high strength, and specific modulus, is combined with plastic materials. However, the combination result poor compatibility because of different properties. Through grafting technique, the compatibility can be improved. The experimental results were conducted using Fourier-Transform Infrared (FT-IR), Simultaneous Thermal Analysis (STA), Scanning Electron Microscope (SEM) and 1H-Nuclear Magnetic Resonance (1H-NMR). The results revealed that the structure of hybrid material consists of cellulose as a chain extender in a hard segment which connects two diisocyanate compounds and polyol as a soft segment. The addition of 2.5 g of cellulose and 5 mole of diisocyanate can increase the melting temperature (Tm) of the hard segment from 417.92 to 460.72 °C and from 417.92 to 467.04 °C respectively. However, its melting temperatures of soft segment decrease from 378.53 to 350.74 °C and from 378.53 to 350.74 °C as well as the glass transition temperature (Tg) of the soft segment from 73.7 to 57.2 °C and from 73.7 to 71.8 °C. This study also discovers that cellulose and diisocyanate can raise thermal stability and create good interfacial bonding.

Effect of Poly(D-Lactic Acid)-co-Polyethylene Glycol on the Crystallization of Poly(L-Lactic Acid)

2017 ◽  
Vol 751 ◽  
pp. 283-289 ◽  
Author(s):  
Ployrawee Kaewlamyai ◽  
Amornrat Lertworasirikul
Keyword(s):  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Weight Ratio ◽  
Crystallization Rate ◽  
Heat Stability ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry

Poly (lactic acid) (PLA) is a biopolymer derived from renewable resources and can be disposed of without creating harm to the environment. PLA can be formed by thermoplastic processes and has good mechanical properties. However, its disadvantages are a high crystallization temperature, slow crystallization rate, poor heat stability and low ductility. In the past, it was found that poly (D-lactic acid) (PDLA) can form complexes with poly (L-lactic acid) (PLLA) and the complexes could accelerate the crystallization and increase the degree of crystallinity of the PLA, but decrease the ductility. It is known that polyethylene glycol (PEG) can improve the ductility of PLLA. In this research, PDLA was copolymerized with PEG in an attempt to improve both crystallization behavior and ductility of PLLA. Poly (D-lactic acid)-co-polyethylene glycol (PDEG) was synthesized by ring opening polymerization using D-lactide and PEG at a D-lactide:PEG weight ratio of 10:3. The PDEG was blended with PLLA with a PDEG content of 0wt% to 50wt% by melt blending process. Fourier transform infrared spectrometry (FT-IR) and X-Ray diffractometry (XRD) confirmed the stereocomplex formation between PDEG and PLLA. Characterization by differential scanning calorimetry (DSC) revealed that crystallization temperatures of the blends were decreased in the presence of PDEG. Storage moduli and tan of the blends obtained from dynamic mechanical analysis (DMA) decreased as PDEG content increased. Polarized optical microscopy (POM) micrographs of blends with PDEG content of 1wt% to 5wt% obviously showed that crystallization rate was increased. PDEG has the potential to be an effective nucleating agent and efficient plasticizer for PLLA.

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