Influence of annealing on microstructure &amp; molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Saengsuwan, Sayant

doi:10.1515/epoly.2008.8.1.1289

Cited by 3 publications

(17 citation statements)

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“…This pattern has been well known as the "smectic phase" of PP as first observed by Natta and Coradini [16]. Generally, the smectic phase of PP can be transformed into the more stable crystalline phase ( -form) through annealing at proper temperature, i.e., 70-150 o C [22][23][24][25][26][27][28]. While, the XRD profiles of annealed composite films in both EQ ( Figure 1a ) and ME ( Figure 1b [16,[24][25][26][27].…”

Section: Microstructure and Molecular Orientation Development During mentioning

confidence: 62%

“…Generally, the smectic phase of PP can be transformed into the more stable crystalline phase ( -form) through annealing at proper temperature, i.e., 70-150 o C [22][23][24][25][26][27][28]. While, the XRD profiles of annealed composite films in both EQ ( Figure 1a ) and ME ( Figure 1b [16,[24][25][26][27]. As the annealing time increases, the XRD intensity profiles in both sections are sharper and more intense, implying that the transformation of smectic phase into monoclinic phase is more pronounced with increasing annealing time [24][25][26][27].…”

Section: Microstructure and Molecular Orientation Development During mentioning

confidence: 99%

“…Although the smectic phase of PP is relatively stable at room temperature, it can be transformed into the monoclinic phase (α-form) by annealing at temperature above 70 C [22][23][24][25][26][27][28]. This morphological transformation can be determined by X-ray diffraction, density, differential scanning calorimetry and dynamic mechanical analysis [23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…This morphological transformation can be determined by X-ray diffraction, density, differential scanning calorimetry and dynamic mechanical analysis [23][24][25][26][27][28]. Moreover, the annealing of PP results in a decrease of amorphous and smectic phases while the -phase fraction, crystal size and degree of perfection are significantly increased, leading to strong improvement in mechanical properties of the PP samples such as Young's modulus, impact/tensile strengths and toughness [22,[25][26][27][28]. Furthermore, it is also well known that annealing of the final polymeric materials causes the various modifications at microscopic level such as reorganization of amorphous segments, rearrangement of crystal segments and reduction of defects and residual stress/strain [29].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, it is also well known that annealing of the final polymeric materials causes the various modifications at microscopic level such as reorganization of amorphous segments, rearrangement of crystal segments and reduction of defects and residual stress/strain [29]. Therefore, the influences of annealing on the mechanical and impact/fracture properties, crystal structure, thermal behavior and morphology of neat PP and its blends are widely explored in the last decade [22][23][24][25][26][27][30][31][32][33]. For example, Poussin et al [25], reported that crystallinity, density and apparent crystal size of the α-phase of PP sheet were rapidly increased in the first 5 min of treatment at 125 °C due to the favorite of molecular mobility in the amorphous phases.…”

Section: Introductionmentioning

confidence: 99%

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correlations of mechanical properties and microstructural parameters in annealed drawn film of liquid crystalline polymer in situ reinforced PP

Saengsuwan

2011

E-Polymers

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Drawn composite thin film based on thermotropic liquid crystalline polymer (TLCP) and polypropylene (PP) was annealed at 130 o C at different times. The influence of annealing time on microstructural and mechanical properties of the composite film has been studied. The correlation in mechanical properties and their microstructural parameters has also been investigated. X-Ray diffraction results reveal that the smectic mesophase transforms progressively into the monoclinic phase as annealing time is increased. Consequently, the true crystallinity (X c ), crystal thickness (L) as well as relative level of molecular orientation of PP crystalline phase in the annealed TLCP/PP films are increased significantly. Also, the TLCP fibrils have no influence on the microstructure of PP crystalline phase. The apparent crystallinity (X c,a ) of PP phase evaluated by DSC also increase significantly with annealing time. As a result, the increases of these microstructural parameters coupled with the reinforcement of TLCP fibrils could be contributed directly to the remarkable enhancement of mechanical properties of the annealed TLCP/PP film in both machine (MD) and transverse (TD) directions. The correlation of moduli with microstructural parameters (X c , X c,a and L) exhibits nonlinear relations. However, the relative level of molecular orientation is a more suitable parameter to correlate with the improvement of mechanical properties of the annealed TLCP/PP film. Finally, this work presents that the mechanical properties of the TLCP in situ reinforced thermoplastics can be significantly enhanced via a simple thermal treatment.

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Section: Microstructure and Molecular Orientation Development During mentioning

confidence: 62%

Section: Microstructure and Molecular Orientation Development During mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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correlations of mechanical properties and microstructural parameters in annealed drawn film of liquid crystalline polymer in situ reinforced PP

Saengsuwan

2011

E-Polymers

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The effect of high temperature annealing process on crystallization process of polypropylene, mechanical properties, and surface quality of plastic parts

Zhao

Wú

Zhai

2015

J of Applied Polymer Sci

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This work studied the effects and action mechanism of high-temperature annealing process parameters, such as annealing temperature, annealing duration and cooling speed, on the microstructural evolution of polypropylene (PP) on different thickness layers, the surface quality, and mechanical properties of PP plastic parts. The results show that when the PP plastic parts are annealed at slightly higher than 1008C, the resin on the surface and internal layers of plastic parts just generates the relaxation and rearrangement at the molecular level. Only at an enough high annealing temperature, the secondary crystallization and phase transformation process can be observed. The crystallinity of all annealed samples is higher than that of unannealed samples, but the crystallinity is decreased with the increase of cooling speed after annealing duration, and the annealing duration exceeding 60 min almost has no effect on the crystallinity. The microstructural change of PP on the internal layer of plastic parts is weaker than that on the surface layer. The surface hardness of the plastic parts mainly depends on the crystallinity of the surface layer, whereas the surface roughness of the plastic parts depends on not only the crystallinity, but also the space conformation of molecular chains and the residual stress. With the change of annealing process parameters, the tensile and impact strengths of plastic parts show a non-monotonic change law.

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Studies on changes in the temperature field and recrystallization properties of glass fiber reinforced polypropylene composite strip winding process

Zhao

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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The glass fiber reinforced polypropylene (GF/PP) composite ring specimens were fabricated based on the composites prepreg tape winding process. The heated winding process was simulated by ANSYS software to obtain the temperature distribution of the wound layer of the specimen. At the same time, the temperature of the wound layer was collected and stored using a temperature-controlled recorder. The temperature fields between the wound layers were found to be different significantly, and the temperature measured through experiments was generally below the simulation results, where it is especially noticeable in the fusion zone. After the recrystallization of GF/PP specimen, the maximum shear strength that the specimen can withstand was improved. The response surface method was used to test and analyze the influence of recrystallization on the mechanical properties of the specimen, Obtain optimized process parameters, heating temperature of 91 °C, pressure of the press roller is 106 N, heating time of 13 min, the highest sample obtained is 28.67Mpa. The experimental results show that the influence of recrystallization parameters on the mechanical properties of the composite specimens (from large to small) are: heating temperature, heating time, and the roller pressure.

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Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Cited by 3 publications

References 35 publications

correlations of mechanical properties and microstructural parameters in annealed drawn film of liquid crystalline polymer in situ reinforced PP

correlations of mechanical properties and microstructural parameters in annealed drawn film of liquid crystalline polymer in situ reinforced PP

The effect of high temperature annealing process on crystallization process of polypropylene, mechanical properties, and surface quality of plastic parts

Studies on changes in the temperature field and recrystallization properties of glass fiber reinforced polypropylene composite strip winding process

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