Thermal Analysis of Crystallization and Phase Transition in Novel Polyethylene Glycol Grafted Butene-1 Copolymers

Copolymerization is an effective strategy to regulate the molecular structure and tune crystalline structures. In this work, novel butene-1 copolymers with different polyethylene glycol (PEG) grafts (number-average molecular weight Mn = 750, 2000, and 4000 g/mol) were synthesized, for the first time introducing long-chain grafts to the polybutene-1 main chain. For these PEG-grafted copolymers, crystallization, melting, and phase transition behaviors were explored using differential scanning calorimetry. With respect to the linear homopolymer, the incorporation of a trimethylsilyl group decreases the cooling crystallization temperature (Tc), whereas the presence of the long PEG grafts unexpectedly elevates Tc. For isothermal crystallization, a critical temperature was found at 70 °C, below which all polyethylene glycol-grafted butene-1 (PB-PEG) copolymers have faster crystallization kinetics than polybutene-1 (PB). The subsequent melting process shows that for the identical crystallization temperature, generated PB-PEG crystallites always have lower melting temperatures than that of PB. Moreover, the II-I phase transition behavior of copolymers is also dependent on the length of PEG grafts. When form II, obtained from isothermal crystallization at 60 °C, was annealed at 25 °C, PB-PEG-750, with the shortest PEG grafts of Mn = 750 g/mol, could have the faster transition rate than PB. However, PB-PEG-750 exhibits a negative correlation between transition rate and crystallization temperature. Differently, in PB-PEG copolymers with PEG grafts Mn = 2000 and 4000 g/mol, transition rates rise with elevating crystallization temperature, which is similar with homopolymer PB. Therefore, the grafting of the PEG side chain provides the available method to tune phase transition without sacrificing crystallization capability in butene-1 copolymers.

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The Melting Behavior of Poly(Ethylene Terephthalate)/ Attapulgite Nanocomposites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.773.530 ◽

2013 ◽

Vol 773 ◽

pp. 530-533

Author(s):

Chen Liu ◽

Xiang Hui Lu ◽

Xue Qi ◽

Peng Li

Keyword(s):

Crystallization Temperature ◽

Isothermal Crystallization ◽

Ethylene Terephthalate ◽

Melting Process ◽

Melting Behavior ◽

Crystallization Time ◽

Scanning Calorimetry ◽

Poly Ethylene Terephthalate ◽

Poly Ethylene ◽

Crystallization From The Melt

The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/ Attapulgite(At)nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of At contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/At nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of At content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.

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The Melting and Recrystallization Behavior of Poly(ethylene Terephthalate)/SiO2 Nanocomposites Studied by Step-Scan DSC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.87-88.69 ◽

2009 ◽

Vol 87-88 ◽

pp. 69-73

Author(s):

Chen Liu ◽

Kang Zheng ◽

Xia Yin Yao ◽

Xian Zhang ◽

Xiang Lan Liu ◽

...

Keyword(s):

Crystallization Temperature ◽

Isothermal Crystallization ◽

Ethylene Terephthalate ◽

Melting Process ◽

Crystallization Time ◽

Recrystallization Behavior ◽

Scanning Calorimetry ◽

Poly Ethylene Terephthalate ◽

Sio2 Nanocomposites ◽

Poly Ethylene

The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/SiO2 nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of SiO2 contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/SiO2 nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of SiO2 content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.

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The effect of isothermal crystallization on mechanical properties of poly(ethylene 2,5-furandicarboxylate)

e-Polymers ◽

10.1515/epoly-2022-0001 ◽

2021 ◽

Vol 22 (1) ◽

pp. 1-11

Author(s):

Wei Zhang ◽

Qingyin Wang ◽

Gongying Wang ◽

Shaoying Liu

Keyword(s):

Mechanical Properties ◽

Intrinsic Viscosity ◽

Crystallization Temperature ◽

Isothermal Crystallization ◽

Tensile Modulus ◽

Optical Microscope ◽

Crystallization Time ◽

Scanning Calorimetry ◽

Crystallization Properties ◽

Poly Ethylene

Abstract The effects of isothermal crystallization temperature/time on mechanical properties of bio-based polyester poly(ethylene 2,5-furandicarboxylate) (PEF) were investigated. The intrinsic viscosity, crystallization properties, thermal properties, and microstructure of PEF were characterized using ubbelohde viscometer, X-ray diffraction, polarizing optical microscope, differential scanning calorimetry, and scanning electron microscopy. The PEF sample isothermal crystallized at various temperatures for various times was denoted as PEF-T-t. The results showed that the isothermal crystallization temperature affected the mechanical properties of PEF-T-30 by simultaneously affecting its crystallization properties and intrinsic viscosity. The isothermal crystallization time only affected the crystallization properties of PEF-110-t. The crystallinity of PEF-110-40 was 17.1%. With small crystal size, poor regularity, and α′-crystal, PEF-110-40 can absorb the energy generated in the tensile process to the maximum extent. Therefore, the best mechanical properties can be obtained for PEF-110-40 with the tensile strength of 43.55 MPa, the tensile modulus of 1,296 MPa, and the elongation at a break of 13.36%.

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Preparation and Characterization of Films Based on a Natural P(3HB)/mcl-PHA Blend Obtained through the Co-culture of Cupriavidus Necator and Pseudomonas Citronellolis in Apple Pulp Waste

Bioengineering ◽

10.3390/bioengineering7020034 ◽

2020 ◽

Vol 7 (2) ◽

pp. 34 ◽

Cited By ~ 2

Author(s):

Ana Teresa Rebocho ◽

João R. Pereira ◽

Luísa A. Neves ◽

Vítor D. Alves ◽

Chantal Sevrin ◽

...

Keyword(s):

Average Molecular Weight ◽

Young Modulus ◽

Cupriavidus Necator ◽

Solvent Evaporation Method ◽

Blend Films ◽

Melting Temperatures ◽

Medium Chain Length ◽

Fruit Processing ◽

First Time

The co-culture of Cupriavidus necator DSM 428 and Pseudomonas citronellolis NRRL B-2504 was performed using apple pulp waste from the fruit processing industry as the sole carbon source to produce poly(3-hydroxybutyrate), P(3HB) and medium-chain length PHA, mcl-PHA, respectively. The polymers accumulated by both strains were extracted from the co-culture’s biomass, resulting in a natural blend that was composed of around 48 wt% P(3HB) and 52 wt% mcl-PHA, with an average molecular weight of 4.3 × 105 Da and a polydispersity index of 2.2. Two melting temperatures (Tm) were observed for the blend, 52 and 174 °C, which correspond to the Tm of the mcl-PHA and P(3HB), respectively. P(3HB)/mcl-PHA blend films prepared by the solvent evaporation method had permeabilities to oxygen and carbon dioxide of 2.6 and 32 Barrer, respectively. The films were flexible and easily deformed, as demonstrated by their tensile strength at break of 1.47 ± 0.07 MPa, with a deformation of 338 ± 19% until breaking, associated with a Young modulus of 5.42 ± 1.02 MPa. This study demonstrates for the first time the feasibility of using the co-culture of C. necator and P. citronellolis strains to obtain a natural blend of P(3HB)/mcl-PHA that can be processed into films suitable for applications ranging from commodity packaging products to high-value biomaterials.

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Study on the Melting Mechanism of Maleic Anhydride

Current Physical Chemistry ◽

10.2174/1877946809666191011155328 ◽

2020 ◽

Vol 10 (1) ◽

pp. 65-78

Author(s):

Bratati Das ◽

Ashis Bhattacharjee

Keyword(s):

Phase Transition ◽

Activation Energy ◽

Maleic Anhydride ◽

Temperature Dependence ◽

Growth Models ◽

Melting Process ◽

Nucleation And Growth ◽

Crystalline Solid ◽

Scanning Calorimetry ◽

Melting Mechanism

Background: Melting of a pure crystalline material is generally treated thermodynamically which disregards the dynamic aspects of the melting process. According to the kinetic phenomenon, any process should be characterized by activation energy and preexponential factor where these kinetic parameters are derivable from the temperature dependence of the process rate. Study on such dependence in case of melting of a pure crystalline solid gives rise to a challenge as such melting occurs at a particular temperature only. The temperature region of melting of pure crystalline solid cannot be extended beyond this temperature making it difficult to explore the temperature dependence of the melting rate and consequently the derivation of the related kinetic parameters. Objective: The present study aims to explore the mechanism of the melting process of maleic anhydride in the framework of phase transition models. Taking this process as just another first-order phase transition, occurring through the formation of nuclei of new phase and their growth, particular focus is on the nucleation and growth models. Methods: Non-isothermal thermogravimetry, as well as differential scanning calorimetry studies, has been performed. Using isoconversional kinetic analysis, temperature dependence of the activation energy of melting has been obtained. Nucleation and growth models have been utilized to obtain the theoretical temperature dependencies for the activation energy of melting and these dependencies are then compared with the experimentally estimated ones. Conclusion: The thermogravimetry study indicates that melting is followed by concomitant evaporation, whereas the differential scanning calorimetry study shows that the two processes appear in two different temperature regions, and these differences observed may be due to the applied experimental conditions. From the statistical analysis, the growth model seems more suitable than the nucleation model for the interpretation of the melting mechanism of the maleic anhydride crystals.

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Interaction of plant alkaloid, berberine, with zwitterionic and negatively charged phospholipid bilayers

Current Topics in Biophysics ◽

10.2478/v10214-011-0007-0 ◽

2011 ◽

Vol 34 (1) ◽

pp. 45-51 ◽

Cited By ~ 2

Author(s):

Justyna Gąsiorowska ◽

Olga Wesołowska ◽

Krystyna Michalak

Keyword(s):

Phase Transition ◽

Differential Scanning Calorimetry ◽

Fluorescence Quenching ◽

Electrostatic Interactions ◽

Phospholipid Bilayers ◽

Scanning Calorimetry ◽

Double Peak ◽

Pharmacological Activities ◽

First Time ◽

Thermotropic Properties

Interaction of plant alkaloid, berberine, with zwitterionic and negatively charged phospholipid bilayers Berberine exhibits many pharmacological activities e.g. antibacterial, anti-inflammatory, antiproliferative and apoptosis-inducing. Interaction of berberine with model membranes was studied for the first time using differential scanning calorimetry, fluorescence spectroscopy and turbidity measurements. Influence of berberine on thermotropic properties of bilayers formed from zwitterionic DMPC was insignificant, whereas in bilayers formed from negatively charged DMPG berberine reduced the temperature and cooperativity of main phospholipid phase transition. In higher concentrations berberine induced complex double-peak transition, with the new peak appearing in temperature higher than the original one. It suggested the interaction of the alkaloid with lipid headgroup region of the bilayer. Additionally, berberine quenched fluorescence of Prodan to a higher extent than Laurdan that pointed to stronger interaction with membrane segments close to its surface. Berberine-induced fluorescence quenching of both probes was more pronounced in DPPG than in DPPC bilayers. It was concluded that electrostatic interactions governed berberine association with model membrane.

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Preparation and Characterization of a Novel Polyurethane Solid-Solid Phase Change Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.613 ◽

2013 ◽

Vol 785-786 ◽

pp. 613-617

Author(s):

Gui Fang Wang ◽

Dong Ying Li ◽

Guang Ling Pei

Keyword(s):

Phase Transition ◽

Polyethylene Glycol ◽

Phase Change ◽

Phase Change Materials ◽

Solid Phase ◽

Soft Segment ◽

Condensation Reaction ◽

Diphenylmethane Diisocyanate ◽

Scanning Calorimetry ◽

Polarization Optical Microscopy

A novel solid-solid phase change materials was synthesized by the two-step condensation reaction of polyethylene glycol (PEG1000), neopentyl glycol (NPG) and 4, 4-diphenylmethane diisocyanate (MDI). Polyethylene glycol (PEG1000) was used as soft segment and 4, 4-diphenylmethane diisocyanate (MDI) as hard segment. The composition, structure and phase change properties were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), polarization optical microscopy (POM) respectively. The results indicated that the PCM appeared typical solid-solid phase transition property and the phase change enthalpy and phase transition temperature reached to 120.45 J/g and 37.32°C, respectively.

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Synthesis of V2O3/C composites with different morphologies by a facile route and phase transition properties of the compounds

Materials Science-Poland ◽

10.2478/s13536-013-0177-6 ◽

2014 ◽

Vol 32 (2) ◽

pp. 236-242 ◽

Cited By ~ 7

Author(s):

Yifu Zhang ◽

Nannan Wang ◽

Yuting Huang ◽

Chi Huang ◽

Xiao Mei ◽

...

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Hydrothermal Route ◽

Scanning Calorimetry ◽

Transmission Electron ◽

Facile Hydrothermal Route ◽

Potential Applications ◽

Subsequent Calcination ◽

Ft Ir ◽

First Time

AbstractV2O3 and amorphous carbon composites (V2O3/C composites) with different morphologies (e.g. nanospheres, nanorods and nanosheets) were, for the first time, successfully synthesized by a facile hydrothermal route and subsequent calcination. The as-obtained samples were characterized by X-ray powder diffraction (XRD), energy dispersive spectrometery (EDS), elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The morphology of V2O3/C composites could be easily controlled by varying the reaction time, and, as a result, V2O3/C composites with nanospheres, nanorods and nanosheets were selectively synthesized. Furthermore, the phase transition property of V2O3/C composites was measured by differential scanning calorimetry (DSC), suggesting that V2O3/C composites exhibit the phase transition similar to V2O3, which could expand the potential applications of materials related to V2O3 in the future.

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Non-Isothermal Crystallization Kinetics of Poly(4-Hydroxybutyrate) Biopolymer

Molecules ◽

10.3390/molecules24152840 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2840 ◽

Cited By ~ 4

Author(s):

Ina Keridou ◽

Luis J. del Valle ◽

Lutz Funk ◽

Pau Turon ◽

Lourdes Franco ◽

...

Keyword(s):

Growth Rate ◽

Cooling Rate ◽

Crystallization Temperature ◽

Isothermal Crystallization ◽

Secondary Nucleation ◽

Scanning Calorimetry ◽

Limited Region ◽

First Case ◽

Biodegradable Poly ◽

Insertion Mechanism

The non-isothermal crystallization of the biodegradable poly(4-hydroxybutyrate) (P4HB) has been studied by means of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In the first case, Avrami, Ozawa, Mo, Cazé, and Friedman methodologies were applied. The isoconversional approach developed by Vyazovkin allowed also the determination of a secondary nucleation parameter of 2.10 × 105 K2 and estimating a temperature close to 10 °C for the maximum crystal growth rate. Similar values (i.e., 2.22 × 105 K2 and 9 °C) were evaluated from non-isothermal Avrami parameters. All experimental data corresponded to a limited region where the polymer crystallized according to a single regime. Negative and ringed spherulites were always obtained from the non-isothermal crystallization of P4HB from the melt. The texture of spherulites was dependent on the crystallization temperature, and specifically, the interring spacing decreased with the decrease of the crystallization temperature (Tc). Synchrotron data indicated that the thickness of the constitutive lamellae varied with the cooling rate, being deduced as a lamellar insertion mechanism that became more relevant when the cooling rate increased. POM non-isothermal measurements were also consistent with a single crystallization regime and provided direct measurements of the crystallization growth rate (G). Analysis of the POM data gave a secondary nucleation constant and a bell-shaped G-Tc dependence that was in relative agreement with DSC analysis. All non-isothermal data were finally compared with information derived from previous isothermal analyses.

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Synthesis of VO2(A) Nanostructures by a Hydrothermal Method and their Transition to VO2(M)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.368 ◽

2011 ◽

Vol 295-297 ◽

pp. 368-372 ◽

Cited By ~ 3

Author(s):

Ya Lan Zhong ◽

Yi Fu Zhang ◽

Xin Liu ◽

Xing Hai Liu ◽

Chi Huang ◽

...

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

Differential Scanning Calorimetry ◽

Hydrothermal Method ◽

Scanning Calorimetry ◽

Facile Hydrothermal Method ◽

X Ray ◽

Transmission Electron ◽

First Time

VO2(A) nanobelts have been synthesized using V2O5, H2O2, ethanol, H2O as the starting materials through a facile hydrothermal method. The as-obtained products were characterized by X-ray powder diffraction (XRD), X-ray photoelecton spectroscopy (XPS), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Some parameters, such as, the reaction time, reaction temperature and the ratio of EtOH/H2O, have greatly influenced on the phases and morphologies of the final products. It was found that VO2(A) can be converted to VO2(M) at 700 °C for 2 h for the first time. Furthermore, the phase transition properties of VO2(A) and VO2(M) phases were respectively studied.

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