WAXD and SAXS for PA1010+BMI system have been measured. The results obtained with the help of Ruland and ID EDCF. showed that Wc1x1, the long period L and the thickness of the crystal lamellae do decreased with BMI co...WAXD and SAXS for PA1010+BMI system have been measured. The results obtained with the help of Ruland and ID EDCF. showed that Wc1x1, the long period L and the thickness of the crystal lamellae do decreased with BMI content at PA10101+BMI system. Comparing both experimental and calculated densitl c values indicated thst the values were of better conformity. Adding BHI into PA1010 caused an increase in distortion.The results from SAXS analysis have also led to the conclusion that a crystal-amorphous interphase could exist in lamellae of Semicrystalline polymers and a three-phase model instead of traditional two-phase model should be used.展开更多
alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was high...alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.展开更多
Structures and crystal form transition of the novel aryl ether ketone polymer containing meta-phenylene linkage: PEKEKK(T/I) were investigated by wide angle X-ray diffraction (WAXD), imaging plates (IPs) and small ang...Structures and crystal form transition of the novel aryl ether ketone polymer containing meta-phenylene linkage: PEKEKK(T/I) were investigated by wide angle X-ray diffraction (WAXD), imaging plates (IPs) and small angle X-ray scattering (SAXS). The energy of activation of the decomposition reaction and degree of crystallinity of PEKEKK(T/I) were determined by WAXD and thermo-gravimetric analysis (TGA), respectively. Results obtained from WAXD and IPs show that crystal forms coexist in the PEKEKK(T/I) samples isothermally cold crystallized in the temperature range from 180'C to 240T? and only form occurs in PEKEKK(TTI) samples isothermally cold crystallized at 2701C. The radius of gyration (Rg), thickness of microregions with electron-density fluctuations (E) and distribution of particle sizes were investigated by SAXS.展开更多
The analysis of the small angle X ray scattering(SAXS) data was based upon particle characteristic function, one dimensional electron density correlation function and particle distribution function. The microstruct...The analysis of the small angle X ray scattering(SAXS) data was based upon particle characteristic function, one dimensional electron density correlation function and particle distribution function. The microstructure of nylon 66 with different degrees of crystallinity was studied by means of X ray scattering method. The radius of gyration R g, the Porod radius R p, the thickness of crystalline region L c, the thickness of non crystalline region L a, the thickness of interphase region d tr , the long period L , the semiaxises of particles( a, a, b ), the distribution of the particle sizes and the scattering invariant were calculated. The results indicate that there was a significant interphase region between the crystalline region and the non crystalline region, and its content( W t,x ) should not be neglected in comparison with that of crystalline region W c,x . The morphology of nylon 66 prepared by isothermal crystallization at a high temperature was mainly a lamellar structure, while the spherical crystals dominated in the quenched sample. The size of the particles in the quenched sample was smaller than that of those in the isothermally crystallized sample, and the distribution of the particle sizes in the isothermally crystallized sample was wider.展开更多
Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of th...Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of the multicomponent polymers were derived in terms of WAXDtheory and improved graphic multipeak resolution methods. The results calculated aresatisfactory in comparison with the density measurement.展开更多
Based on the X-ray scattering intensity theory and using the atomic scattering factorapproximate expression,the correction factors for three main crystalline peaks and an amorphouspeak of Nylon-1010 were calculated an...Based on the X-ray scattering intensity theory and using the atomic scattering factorapproximate expression,the correction factors for three main crystalline peaks and an amorphouspeak of Nylon-1010 were calculated and the formula of degree of crystallinity of Nylon-1010 wasderived by graphic multipeak resolution method. The results calculated are compatible with the density measurement and calorimetry.展开更多
Poly（L-lactic acid） （PLLA） and poly（e-caprolactone） （PCL） have been receiving much attention lately due to their biodegradability in human body as well as in the soil, also due to their biocompatibility, envir...Poly（L-lactic acid） （PLLA） and poly（e-caprolactone） （PCL） have been receiving much attention lately due to their biodegradability in human body as well as in the soil, also due to their biocompatibility, environmentally friendly characteristics and non-toxicity. Morphology of biodegradable polymers affects the rate of their biodegradation. A polymer that has high degree of crystallinity will degrade at a slower rate due to the inherent increased stability. PCL homopolymer crosslinking degree increases with increasing doses of high energy radiation. On the other hand, the irradiation ofPLLA homopolymer promotes mainly chain-scissions at doses below 250 kGy. In the present work, twin screw extruded films of PLLA and PCL biodegradable homopolymers and 50：50 （w：w） blend were electron beam irradiated using electron beam accelerator Dynamitron （E = 1.5 MeV） from Radiation Dynamics, Inc. at doses in the range of 50 kGy to 103 kGy in order to evaluate the effect of electron beam radiation. Wide-angle X-ray diffraction （WAXD） patterns of non irradiated and irradiated samples were obtained using a diffractometer Rigaku Denki Co. Ltd., Multiflex model; and Fourier transform infrared spectroscopy （FTIR） spectra was obtained using a NICOLET 4700, attenuated total reflectance （ATR） technique. By WAXD patterns of as extruded non irradiated and irradiated PLLA it was verified broad diffusion peaks corresponding to amorphous polymer. There was a slight increase of the mean crystallite size of PCL homopolymer with increasing radiation dose. PCL crystalline index （CI） decreased with radiation dose above 500 kGy. But then, PLLA CI increased with radiation dose above 750 kGy. From another point of view, PLLA presence on the 50：50 blend did not interfere on the observed mean crystallite size increase up to 250 kGy. From 500 kGy to 103 kGy the crystallite size of PCL was a little bigger in the blend than the homopolymer. In contrast, FTIR results have shown that this technique was not sensitive enough to observe the degradation promoted by ionizing radiation of the studied homopolymers and blends, and neither on the miscibility of the blends.展开更多
Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction （2D SAXS/WAXD）. The SAXS results show that during pre-oxidat...Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction （2D SAXS/WAXD）. The SAXS results show that during pre-oxidation between 180 ℃ and 275 ℃, the volume content of microvoids increases with the temperature increasing, which may be one of reasons for the decrease of tensile strength ofpre-oxidized fibers. 253 ℃ was the critical transition temperature, the length, diameter, aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature. After the high temperature carbonization, lots of spindly microvoids formed. WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 ℃ and then decreased with the increase of temperature during the pre-oxidation. The diffraction peak of PAN fibers at 2θ ≈ 17°almost disappeared at the end of pre- oxidation while the diffraction peak of aromatic structure at 2θ ≈ 25° appeared at 253 ℃. During carbonization, the peak intensity at 2θ ≈ 25° increased apparently due to the formation of graphite structure. The results obtained give a deep understanding of the microstrncture development in the PAN fibers during pre-oxidation and carbonization, which is important for the preparation of high performance carbon fibers.展开更多
文摘WAXD and SAXS for PA1010+BMI system have been measured. The results obtained with the help of Ruland and ID EDCF. showed that Wc1x1, the long period L and the thickness of the crystal lamellae do decreased with BMI content at PA10101+BMI system. Comparing both experimental and calculated densitl c values indicated thst the values were of better conformity. Adding BHI into PA1010 caused an increase in distortion.The results from SAXS analysis have also led to the conclusion that a crystal-amorphous interphase could exist in lamellae of Semicrystalline polymers and a three-phase model instead of traditional two-phase model should be used.
文摘alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.
基金This work was supported by the National Natural Science Foundation of China (No. 270274049) and subsidized by theSpecial Funds for Major State Basic Research Projects (G1999064800).
文摘Structures and crystal form transition of the novel aryl ether ketone polymer containing meta-phenylene linkage: PEKEKK(T/I) were investigated by wide angle X-ray diffraction (WAXD), imaging plates (IPs) and small angle X-ray scattering (SAXS). The energy of activation of the decomposition reaction and degree of crystallinity of PEKEKK(T/I) were determined by WAXD and thermo-gravimetric analysis (TGA), respectively. Results obtained from WAXD and IPs show that crystal forms coexist in the PEKEKK(T/I) samples isothermally cold crystallized in the temperature range from 180'C to 240T? and only form occurs in PEKEKK(TTI) samples isothermally cold crystallized at 2701C. The radius of gyration (Rg), thickness of microregions with electron-density fluctuations (E) and distribution of particle sizes were investigated by SAXS.
基金Supported by the Key Project of National Natural Science Foundation of China(No. 2 99340 72 ) and subsidized by theSpecial Fund for Major State Basic Research Projects(No.G19990 6 4 80 6 ) .
文摘The analysis of the small angle X ray scattering(SAXS) data was based upon particle characteristic function, one dimensional electron density correlation function and particle distribution function. The microstructure of nylon 66 with different degrees of crystallinity was studied by means of X ray scattering method. The radius of gyration R g, the Porod radius R p, the thickness of crystalline region L c, the thickness of non crystalline region L a, the thickness of interphase region d tr , the long period L , the semiaxises of particles( a, a, b ), the distribution of the particle sizes and the scattering invariant were calculated. The results indicate that there was a significant interphase region between the crystalline region and the non crystalline region, and its content( W t,x ) should not be neglected in comparison with that of crystalline region W c,x . The morphology of nylon 66 prepared by isothermal crystallization at a high temperature was mainly a lamellar structure, while the spherical crystals dominated in the quenched sample. The size of the particles in the quenched sample was smaller than that of those in the isothermally crystallized sample, and the distribution of the particle sizes in the isothermally crystallized sample was wider.
基金This work is supported by the National Natural Science Foundation of China and the National Basic Research Project- Macromolecular Condensed State
文摘Based on the X- ray scattering intensity theory, the correction factors of the degree ofcrystallinity formulae of the multicomponent polymers have been clearly defined. The formulae ofthe degree of crystallinity of the multicomponent polymers were derived in terms of WAXDtheory and improved graphic multipeak resolution methods. The results calculated aresatisfactory in comparison with the density measurement.
基金This project was supported by the National Natural Science Foundation of China and the National Basic Research Project Macromolecular Condensed State.
文摘Based on the X-ray scattering intensity theory and using the atomic scattering factorapproximate expression,the correction factors for three main crystalline peaks and an amorphouspeak of Nylon-1010 were calculated and the formula of degree of crystallinity of Nylon-1010 wasderived by graphic multipeak resolution method. The results calculated are compatible with the density measurement and calorimetry.
文摘Poly（L-lactic acid） （PLLA） and poly（e-caprolactone） （PCL） have been receiving much attention lately due to their biodegradability in human body as well as in the soil, also due to their biocompatibility, environmentally friendly characteristics and non-toxicity. Morphology of biodegradable polymers affects the rate of their biodegradation. A polymer that has high degree of crystallinity will degrade at a slower rate due to the inherent increased stability. PCL homopolymer crosslinking degree increases with increasing doses of high energy radiation. On the other hand, the irradiation ofPLLA homopolymer promotes mainly chain-scissions at doses below 250 kGy. In the present work, twin screw extruded films of PLLA and PCL biodegradable homopolymers and 50：50 （w：w） blend were electron beam irradiated using electron beam accelerator Dynamitron （E = 1.5 MeV） from Radiation Dynamics, Inc. at doses in the range of 50 kGy to 103 kGy in order to evaluate the effect of electron beam radiation. Wide-angle X-ray diffraction （WAXD） patterns of non irradiated and irradiated samples were obtained using a diffractometer Rigaku Denki Co. Ltd., Multiflex model; and Fourier transform infrared spectroscopy （FTIR） spectra was obtained using a NICOLET 4700, attenuated total reflectance （ATR） technique. By WAXD patterns of as extruded non irradiated and irradiated PLLA it was verified broad diffusion peaks corresponding to amorphous polymer. There was a slight increase of the mean crystallite size of PCL homopolymer with increasing radiation dose. PCL crystalline index （CI） decreased with radiation dose above 500 kGy. But then, PLLA CI increased with radiation dose above 750 kGy. From another point of view, PLLA presence on the 50：50 blend did not interfere on the observed mean crystallite size increase up to 250 kGy. From 500 kGy to 103 kGy the crystallite size of PCL was a little bigger in the blend than the homopolymer. In contrast, FTIR results have shown that this technique was not sensitive enough to observe the degradation promoted by ionizing radiation of the studied homopolymers and blends, and neither on the miscibility of the blends.
基金financially supported by Innovation Method Fund of China(2011IM030400)NSFC(No.10835008)+4 种基金the Knowledge Innovation Project of CAS(No.KJCX2-YW-N39)973 Program(No.2011CB605604)the Opening Foundation of Shenzhen Key Laboratory of Functional Polymers(FP20120012)Natural Science Foundation of Shenzhen University(Grant no.201204)the Shenzhen basic research project(JCYJ20120614085820810)
文摘Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction （2D SAXS/WAXD）. The SAXS results show that during pre-oxidation between 180 ℃ and 275 ℃, the volume content of microvoids increases with the temperature increasing, which may be one of reasons for the decrease of tensile strength ofpre-oxidized fibers. 253 ℃ was the critical transition temperature, the length, diameter, aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature. After the high temperature carbonization, lots of spindly microvoids formed. WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 ℃ and then decreased with the increase of temperature during the pre-oxidation. The diffraction peak of PAN fibers at 2θ ≈ 17°almost disappeared at the end of pre- oxidation while the diffraction peak of aromatic structure at 2θ ≈ 25° appeared at 253 ℃. During carbonization, the peak intensity at 2θ ≈ 25° increased apparently due to the formation of graphite structure. The results obtained give a deep understanding of the microstrncture development in the PAN fibers during pre-oxidation and carbonization, which is important for the preparation of high performance carbon fibers.
