Studies on the effects of 4,4′-dihydroxyphenyl on crystallization and melting behavior of poly (butylene terephthalate)

2017 ◽  
Vol 37 (8) ◽  
pp. 747-755 ◽  
Author(s):  
Zhiyuan Shen ◽  
Faliang Luo ◽  
Jianghua Du ◽  
Xiaomei Lei ◽  
Lijie Ji
Keyword(s):  
Crystallization Rate ◽  
Melting Behavior ◽  
Avrami Equation ◽  
Wide Angle ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Butylene Terephthalate ◽  
X Ray ◽  
Crystallization And Melting Behavior

Abstract The blends of poly (butylene terephthalate) (PBT) and 4,4′-dihydroxyphenyl (DHP) were prepared by melt blending, and the effects of DHP on the crystallization and melting behaviors of PBT were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and polarized optical microscopy (POM). The results showed that crystallization temperature and crystallinity of PBT apparently decreased with the addition of DHP. A remarkably decline in crystallization rate of PBT was achieved, and the blends had higher σe and q values than that of pure PBT as analyzed based on the Avrami equation and Lauritzen-Hoffman equation. The crystal structure of PBT did not change by the addition of DHP, while the spherulite size of PBT decreased.

Plasticizer effect on melt blending of polylactide stereocomplex

e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 409-416 ◽  
Author(s):  
Yottha Srithep ◽  
Dutchanee Pholharn
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Crystallization Rate ◽  
Wide Angle ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Neat Plla ◽  
Internal Mixer

AbstractPoly(l-lactide) (PLLA)/poly(d-lactide) (50/50) with plasticizer contents ranging from 2% to 16% w/w were prepared by melt blending using an internal mixer. Wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry results confirmed that complete stereocomplex polylactide crystallites without any homocrystallites were produced. Compared to neat PLLA, the melting temperature of the stereocomplex polylactide and its plasticized samples was approximately 55°C higher. Higher plasticizer contents decreased glass transition temperature of the stereocomplex, which implied higher flexibility and enhanced the crystallization rate. However, the plasticizer in the stereocomplex reduced the thermal stability.

scholarly journals Influence of Molecular Orientation on the Melting Behavior of Poly(phenylene sulfide) Fibers

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800
Author(s):  
Prabhakar Gulgunje ◽  
Gajanan Bhat ◽  
Joseph Spruiell
Keyword(s):  
Differential Scanning Calorimetry ◽  
Molecular Orientation ◽  
Polarized Light ◽  
Melting Behavior ◽  
Probable Mechanism ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Phenylene Sulfide

The influence of molecular orientation on the melting behavior of draw-annealed poly(phenylene sulfide) fibers is investigated in the present paper. Tools used to probe the investigation were differential scanning calorimetry, polarized light optical microscopy, wide angle X-ray diffraction, and small angle X-ray diffraction. It is shown that molecular orientation in the crystalline and amorphous regions play a key role in crystal rearrangement during melting. A probable mechanism by which amorphous orientation influences crystal rearrangement is also discussed.

Effect of Montmorillonite Content on Nucleation of Polypropylene

2013 ◽  
Vol 664 ◽  
pp. 538-542 ◽  
Author(s):  
Onusa Saravari ◽  
Phanitnan Srisuwan ◽  
Noppadon Kerddonfag ◽  
Wannee Chinsirikul
Keyword(s):  
Crystal Structure ◽  
Wide Angle ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Nucleation Effect ◽  
Blending Process ◽  
Internal Mixer ◽  
Better Than

In this article, the effect of montmorillonite (MMT) concentration on the nucleation of polypropylene (PP) was investigated. The PP/MMT nanocomposites containing various content of MMT (0.075-3.0 wt%) were prepared by a melt blending process using an internal mixer, followed by compression molding into sheets. The nucleation effect of MMT was characterized by X-ray diffraction (XRD), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) techniques. XRD results indicated that the PP nanocomposites loaded with less than 1.5 wt% of MMT formed an exfoliated structure. DSC results showed that the crystallization temperature (Tc) of PP/MMT nanocomposites were higher than that of neat PP. Tc also increased with increasing MMT content, indicating that MMT was effective in nucleating PP crystal. WAXD patterns revealed that the addition of MMT did not affect the crystal structure of PP. Mechanical property tests showed that the tensile and impact strengths of the PP/MMT nanocomposites were better than those of neat PP when the MMT content was lower than 1.5 wt%.

scholarly journals Effect of Composition on the Crystallization, Water Absorption, and Biodegradation of Poly(ε-caprolactam-co-ε-caprolactone) Copolymers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2488
Author(s):  
Yuanyuan Dou ◽  
Xinyu Mu ◽  
Yuting Chen ◽  
Zhenbo Ning ◽  
Zhihua Gan ◽  
...  
Keyword(s):  
Water Absorption ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Feed Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Molar Feed Ratio ◽  
Anionic Copolymerization

Poly(ester amide)s have aroused extensive research interest due to the combination of the degradability of polyester and the higher mechanical properties of polyamide. In this work, a series of poly(ε-caprolactam-co-ε-caprolactone) (P(CLA-co-CLO)) copolymers with different compositions were synthesized by anionic copolymerization. The structure, crystallization behavior, water absorption, and biodegradation behavior of these copolymers were investigated by means of nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and polarized optical micrographs (POM). The results indicated that the composition of P(CLA-co-CLO) copolymers can be adjusted by the molar feed ratio. The PCL blocks decreased the crystallization rate of PA6 blocks but had little effect on the melting behavior of PA6, while the crystallized PA6 acted as a heterogeneous nucleating agent and greatly improved the crystallization rate of PCL. Moreover, the introduction of PCL blocks greatly reduced the water absorption of P(CLA-co-CLO) copolymers and endow them a certain degree of degradability.

scholarly journals Enantiomeric Polylactide Blends in the Presence of Montmorillonite Clay

2018 ◽  
Vol 34 (6) ◽  
pp. 2716-2720
Author(s):  
Onanong Cheerarot ◽  
Yodthong Baimark
Keyword(s):  
Wide Angle ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Blending Method ◽  
Stereocomplex Formation ◽  
Internal Mixer ◽  
Nanocomposite Structures

The stereocomplex polylactides (scPLAs) of the asymmetric poly(L-lactide)(PLLA)/poly(D-lactide) (PDLA) ratios from 80:20 to 60:40 were prepared via the simple melt blending method using an internal mixer at 200°C. An organo-modified clay, Cloisite® 30B, was used for nanocomposite preparation. The formation of the stereocomplex and nanocomposite structures were confirmed by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). An increase in the PDLA content could enhance the stereocomplex formation. The presence of Cloisite®30B decreased the melting temperature and crystallinity of the blends. This was due to the thinner crystalline size generated and/or more disordered crystals.

Structure and properties of polypropylene/organic rectorite nanocomposites

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Yun Huang ◽  
Xiaoyan Ma ◽  
Guozheng Liang ◽  
Hongxia Yan
Keyword(s):  
Loss Modulus ◽  
Polarized Light ◽  
Clay Content ◽  
Crystal Form ◽  
Ammonium Bromide ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Monoclinic Crystal ◽  
X Ray

AbstractMelt blending using a twin-screw extruder was used to prepare composites of polypropylene (PP)/organic rectorite (PR). The organic rectorite (OREC) was modified with dodecyl benzyl dimethyl ammonium bromide (1227). Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy were used to investigate the dispersion of OREC in the composites. The d spacings of OREC in PR composites was greater than in OREC itself. The dispersion of OREC particles in the PP polymer matrix was fine and uniform when the clay content was small (2 wt.%). The rheology was characterized using a capillary rheometer. The processing behaviour of the PR system improved as the amount of OREC added increased. Non-isothermal crystallization kinetics were analysed using differential scanning calorimetry. It was shown that the addition of OREC had a heterogeneous nucleation effect on PP, and can accelerate the crystallization. However, only when fine dispersion was achieved, and at lower rates of temperature decrease, was the crystallinity greater. Wide-angle X-ray diffraction and polarized light microscopy were used to observe the crystalline form and crystallite size. The PP in the PR composites exhibited an a-monoclinic crystal form, as in pure PP, and in both cases a spherulite structure was observed. However, the smaller spherulite size in the PR systems indicated that addition of OREC can reduce the crystal size significantly, which might improve the ‘toughness’ of the PP. The mechanical properties (tensile and impact strength) improved when the amount of OREC added was appropriate. Dynamic mechanical analysis showed that the storage modulus (E′) and loss modulus (E″) of the nanocomposites were somewhat greater than those of pure PP when an appropriate amount of OREC was added. Finally, thermogravimetric analysis showed that the PR systems exhibited a greater thermal stability than was seen with pure PP.

Polypseudorotaxane Hydrogels Based on F127 Block-Selected Inclusion Complexation with α-Cyclodextrin

2012 ◽  
Vol 482-484 ◽  
pp. 1898-1903
Author(s):  
Ying Xue Zhou ◽  
Xiao Dong Fan ◽  
Dan Xue
Keyword(s):  
Thermal Stability ◽  
Inclusion Complex ◽  
Inclusion Complexation ◽  
Wide Angle ◽  
Acryloyl Chloride ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Thermal Stability Of ◽  
Channel Type

Supramolecular hydrogels were formed through F127, acryloyl chloride modified F127 inclusion complex with α-cyclodextrin, respectively. The structure of modified copolymers and inclusion complex was characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (1H-NMR). Hydrogels formed from supramolecular inclusion are imparted channel-type structure investigated by wide angle x-ray diffraction (WAXRD). Differential scanning calorimetry (DSC) and TG experiments showed that thermal stability of hydrogels depend on the nature of axis polymer. The relative model was proposed to elucidate the inclusion complexes and hydrogels formation.

A New Modifier Prepared and it’s Applied in High-Density Polyethylene/Anhydrite Composites

2011 ◽  
Vol 415-417 ◽  
pp. 390-394
Author(s):  
Shao Hui Wang
Keyword(s):  
High Density Polyethylene ◽  
Bending Strength ◽  
Crystallization Rate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Powder Particles ◽  
Ft Ir ◽  
Anchoring Group ◽  
The Impact

A new Modifier with Silicon radicals as anchoring group and poly(butyl acrylate) as solvatable chain was synthesized and its effect on the properties of HDPE/Anhydrite composites was investigated in this paper. Fourier transmission infrared spectroscopy (FT-IR) results show that the modifier react on the Anhydrite powder particles surface and the modified Anhydrite powder particles particles. compared with that of HDPE/Anhydrite (filled with same non-modified fraction), The impact strength, tensile strength, bending strength and Young’s modulus of modified HDPE/Anhydrite composites increased about 36.6%, 7.5%, 15.6% and 34% respectively. Based on surface analysis by scanning electron microscope (SEM), the Anhydrite powder particles buried well in HDPE matrix when Anhydrite powder particles was coated with the YB modifier. It was found that Anhydrite powder particles significantly increased the crystallization temperature and crystallization rate of HDPE by differential scanning calorimetry (DSC). At same time, through the X-ray diffraction (XRD) found the addition of the YB modifier modified Anhydrite powder particles can not change the formation of crystal HDPE, but can reduce the crystallite size.

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