Simultaneous SAXS/WAXS and d.s.c. analysis of the melting and recrystallization behaviour of quenched polypropylene

O'Kane, W.J.; Young, Robert J.; Ryan, Anthony J.; Bras, Wim; Derbyshire, G.E.; Mant, G.

doi:10.1016/0032-3861(94)90333-6

Cited by 114 publications

(80 citation statements)

References 19 publications

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“…For the unannealed iPP film (UA), the first small endothermic peak ( sm m T ) is quite broader and is located in the temperature range of 45-85 °C with a maximum at about 70 °C. This peak reveals the presence of the smectic metastable phase of iPP and has been attributed to the melting of small monoclinic crystals developed on quenching process of the final product, reported by other research groups [2,3,5,19]. In addition, the value of sm m T can also be taken as a simple indication of the order perfection of the material at different annealing conditions [3].…”

Section: Thermal Propertiesmentioning

confidence: 57%

“…The drop in MD elongation at break of the films annealed at 130 °C compared to that of the unannealed one is about 10 %, whereas the drop in TD elongation at break of the both annealed films is in the same range of ~ 20%. The reduction in elongation at break of the annealed iPP films could be viewed as a result of the reduction of molecular mobility [19,55], the decrease in the portion of smectic and amorphous phases (see Figs. 1-2) and the increase in the degree of perfection of crystallites (see Figs.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…This intermediate state is between ordered and amorphous phases, and widely known by various names such as "quenched" [19], "mesomorphic" [20,21], "paracrystalline" [22], nano-crystallites [23], condis crystal [24] and a well known "smectic" phase [25][26][27]. Later, it was also found that the smectic phase could be obtained by cold drawing of iPP film at room temperature [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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

Saengsuwan

2008

E-Polymers

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Abstract:The influence of annealing on the microstructure and molecular orientation, thermal behaviour and mechanical properties of uniaxially drawn iPP thin film was studied by wide-angle X-ray diffraction, differential scanning calorimetry and tensile testing, respectively. The correlations of mechanical and microstructural properties of annealed films were also examined. The transformation of smectic phase of iPP to the α-form was more pronounced with increasing annealing time and temperature. The true and apparent crystallinities and crystal thickness were strongly enhanced with annealing time and temperature. The relative molecular orientation tended to increase with annealing time. These results caused the significant improvement of modulus and tensile strength of the annealed films in both machine (MD) and transverse (TD) directions. The increases in MD-Young's modulus and MD-tensile strength were well correlated with the increase in true crystallinity obtained in equatorial scans. Some relationship between the increase in crystal thickness and the increase in Young's modulus in both MD and TD directions was also found.

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Section: Thermal Propertiesmentioning

confidence: 57%

Section: Mechanical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Saengsuwan

2008

E-Polymers

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“…This indicates that the tensile ductility of annealed samples decreases rapidly, which is a typical characteristic of short-fiber reinforced polymer composites with highly mechanical properties [1][2][3][4]. The drop in EB of annealed TLCP/PP composites is probably due to the decrease of various factors such as; molecular mobility [38], the portion of smectic and amorphous phases, physical cross-link degree of amorphous phase [37], the interphase interaction between PP phase and TLCP fibrils [6], and the increase in the perfection degree of crystallites [37].…”

Section: Mechanical Propertiesmentioning

confidence: 99%

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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“…New developments are spearheaded by the most demanding of applications, i.e. fast time-resolved, combined-technique and twodimensional data-producing experiments, small-angle scattering (SAXS)/wide-angle scattering/differential scanning calorimetry, quick EXAFS/X-ray diffraction, small-angle diffraction/wide-angle diffraction, SAXS/Fourier-transform infrared spectroscopy Sankar et al, 1993;Bras et al, 1993;O'Kane et al, 1994), some of which are controlled by VME-based systems networked to Unix workstations. In cases where the appropriate VME modules are not yet available, a hybrid approach of a VME processor interfaced to CAMAC has been used as an interim solution.…”

Section: Data Acquisitionmentioning

confidence: 99%

Computing for Synchrotron Radiation Experiments

Ackroyd¹,

Campbell²,

Dean³

et al. 1994

J Synchrotron Radiat

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Computing provision is of major concern to synchrotron radiation researchers. An overview is presented of the computing facilities for synchrotron radiation work at the Synchrotron Radiation Source, Daresbury Laboratory. Data acquisition, reduction and analysis are seen as an integrated activity essential for full utilization of beam time. We discuss the evolution of data-acquisition systems from stand-alone systems of limited computing power, to a unified project computing village using state-of-the-art equipment for combined-technique, high-data-rate experiments. A brief account of software packages for data reduction and analysis is also given.

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Simultaneous SAXS/WAXS and d.s.c. analysis of the melting and recrystallization behaviour of quenched polypropylene

Cited by 114 publications

References 19 publications

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

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

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

Computing for Synchrotron Radiation Experiments

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