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In this paper, the mesostructures and formation mechanism of Ag/SBA-15 nanocomposites by in-situ "pH-adjusting" method were studied. Characterization results, such as X-ray powder diffraction, N2 adsorption-desorption isotherms and Transmission electron microscope, showed that the resultant materials exhibited highly ordered hexagonal mesoporous structures, which were strongly correlated to the pH values in the synthesis solution. The pH value also strongly affected the incorporation of silver nanoparticles into the channels. When the pH value of the solution was < or = 7.5, the highly ordered Ag/SBA-15 nanocomposites were synthesized successfully; moreover, more and more Ag(NH3)+ reacts with Si-OH groups in the channels, which resulted in the increase of silver nanoparticles in the channels with the increase of the pH value. Further increasing the pH value, overmuch OH- reacts with Ag+, leading to the decrease of the coated Ag species and the structural order of Ag/SBA-15 nanocomposites. It was found that silver ions could be automatically reduced to silver atoms during the crystallization procedure.

Freeze casting of aqueous suspensions was investigated as a method for preparing porous hydroxyapatite (HA) scaffolds for eventual application to bone tissue engineering. Suspensions of HA particles (10-20 volume percent) were frozen unidirectionally in a cylindrical mold placed on a cold steel substrate (-20 degrees C). After sublimation of the ice, sintering for 3 h at 1350 degrees C produced constructs with dense HA lamellae, with porosity of approximately 50%, and inter-lamellar pore widths of 5-30 microm. These constructs had compressive strengths of 12 +/- 1 MPa and 5 +/- 1 MPa in the directions parallel and perpendicular to the freezing direction, respectively. Manipulation of the microstructure was achieved by modifying the solvent composition of the suspension used for freeze casting. The use of water-glycerol mixtures (20 wt% glycerol) resulted in the production of constructs with finer pores (1-10 microm) and a larger number of dendritic growth connecting the HA lamellae, and higher strength. On the other hand, the use of water-dioxane mixtures (60 wt% dioxane) resulted in a cellular-type microstructure with larger pores (90-110 microm). The mechanical response showed high strain tolerance (5-10% at the maximum stress), high strain for failure (>20%) and sensitivity to the loading rate. The favorable mechanical behavior of the porous constructs, coupled with the ability to modify their microstructure, indicates the potential of the present freeze casting route for the production of porous scaffolds for bone tissue engineering.

High-throughput screening and optimization experiments are critical to a number of fields, including chemistry and structural and molecular biology. The separation of these two steps may introduce false negatives and a time delay between initial screening and subsequent optimization. Although a hybrid method combining both steps may address these problems, miniaturization is required to minimize sample consumption. This article reports a "hybrid" droplet-based microfluidic approach that combines the steps of screening and optimization into one simple experiment and uses nanoliter-sized plugs to minimize sample consumption. Many distinct reagents were sequentially introduced as approximately 140-nl plugs into a microfluidic device and combined with a substrate and a diluting buffer. Tests were conducted in approximately 10-nl plugs containing different concentrations of a reagent. Methods were developed to form plugs of controlled concentrations, index concentrations, and incubate thousands of plugs inexpensively and without evaporation. To validate the hybrid method and demonstrate its applicability to challenging problems, crystallization of model membrane proteins and handling of solutions of detergents and viscous precipitants were demonstrated. By using 10 microl of protein solution, approximately 1,300 crystallization trials were set up within 20 min by one researcher. This method was compatible with growth, manipulation, and extraction of high-quality crystals of membrane proteins, demonstrated by obtaining high-resolution diffraction images and solving a crystal structure. This robust method requires inexpensive equipment and supplies, should be especially suitable for use in individual laboratories, and could find applications in a number of areas that require chemical, biochemical, and biological screening and optimization.

High-density well-aligned ZnO nanorod array was successfully synthesized on a large-area magnetron sputtering deposited Al doped ZnO film-coated Si (AZO/Si) substrate via a convenient solution method. X-ray diffraction and scanning electron microscopy show that the nanorods are well-oriented perpendicular to the substrate. The influences of the reaction temperature, time, on the size and shapes of the as-prepared ZnO nanorods (ZNs) samples have been studied. The length and diameter of the nanorods became bigger when a longer reaction time was used. When the temperature is elevated to 130 degrees C, a new conical ZNs was synthesized. Room-temperature photoluminescence (PL) spectra of all the ZnO products showed a strong ultraviolet (UV) emission. The photoluminescence from free excitons of the ZNs synthesized at higher temperature reflects the high purity and nearly defect free structure of nanorods. The well-aligned feature of the nanorod array is attributed to the nanorods' epitaxial growth from the AZO films.

ZnO nanostructures including nanorod and nanotower were synthesized on Ag nanoisland coated Si substrate by thermal evaporation and vapor phase transport at atmospheric pressure. The as-prepared ZnO nanorods and nanotowers were single crystal growing along [0001] direction. The growth of ZnO nanostructures strongly depended on the surface morphology of the nanoisland Ag film deposited by electroless nanoelectrochemistry. The growth mechanism of the ZnO nanostructures was proposed on the basis of experimental data. A strong room-temperature photoluminescence in ZnO nanostructures has been demonstrated. The growth technique would be of particular interest for direct integration in the current silicon-technology-based optoelectronic devices.

This article focus on derive the process-structure-property relationship of Poly(L-lactide) (PLLA) fibers prepared by two-step melt spinning process. The spinning temperature, spinning rate, drawing temperature as well as draw ratio were studied to analyze the influence of process variables on the structure and properties of PLLA fibers. It suggests that the crystallinity, lamellar orientation structure and mechanical properties of fibers are dependent on the spinning conditions, including melt-spinning and hot-drawing process. An approximate linear correlation resulted between the orientation degree and tensile strength of PLLA fibers, which means that the oriented structure plays a dominant role to enhance PLLA fibers. PLLA fibers with high performance of 499 MPa and 5.30 GPa in tensile strength and Young's modulus separately have been realized by the selected spinning parameters. The results provide a theoretical direction for enhancing PLLA fibers by adjusting the structure characteristic via modifying the spinning parameters. [ABSTRACT FROM AUTHOR]

Many experimental results have revealed that entanglement networks of molecular chain would undergo the orientation, deformation, and breakdown under the condition with shear field, forming a new conformation with much reduced entanglement interactions with the surrounding medium. In this work, the role of shear mode on the disentanglement of chains was investigated to give us some guidance for designing a new polymer melts disentanglement machine to optimize the processability of polymers by reducing viscosity. Results showed that the intensity of the generated shear modification depends on shear procedure during treatment, ramping‐up shear has the most efficient influence on molecular chains disentanglement due to the absence of shear banding, resulting in a higher molecular weight between entanglements Me and much lower entanglement density. Besides, the reduced entanglement density enabled the higher chain mobility, which greatly enhanced crystallization kinetics during non‐isothermal and isothermal crystallization. [ABSTRACT FROM AUTHOR]

Constructing stereocomplex (SC) crystallites at the interface of poly(L‐lactide) (PLLA)/elastomer blends represent a promising strategy to develop heat‐resistant and super‐tough PLLA materials because such SC crystallites can behave as not only nucleator to accelerate crystallization of PLLA matrix but also interfacial binder to strengthen interface. The properties of blends could be largely dominated by the SC interfacial layer, however, it is still unclear how the interfacial structure affects nucleating efficiency and interfacial strength. Herein, taking PLLA/poly(ethylene‐co‐methyl acrylate‐graft‐poly(D‐lactide)) (EMA‐g‐PDLA) blends as an example, EMA‐g‐PDLA bearing different chain lengths and grafting densities is prepared to tailor the size and packing density of interface‐localized SC crystallites. The results indicate that the interfacial structure and properties of the blends have been successfully manipulated. Compared with low‐graft‐density long PDLA chains, high‐graft‐density short ones can readily collaborate with PLLA chains to form numerous SC crystallites with smaller size and higher packing density at the interface and thus dramatically enhance the impact toughness and matrix crystallization rate. Moreover, the toughness is dominated by the content of SC crystallites, but the matrix crystallization is determined by their size and packing density. The work provides a new understanding of SC structure controlling the properties of PLLA/elastomer blends. [ABSTRACT FROM AUTHOR]

Chain entanglement, either cohesional or topological, distinguishes polymers from other engineering materials. It impedes the movement of molecular segments and influences the polymer rheology, morphology, and mechanical properties. Although a high level of entanglement can increase the polymer toughness, excessive entanglement should be avoided because it causes a high melt viscosity making the processing difficult. This review tended to elucidate the influence of entanglement on the polymer structure, determining the material properties and processability. A wide range of methods used to fine control the degrees of chain entanglement are summarized. The methods are applicable to polymers in solutions, melts, and condensed states with advantages and limitations discussed in detail. The authors also examined the effect of the entanglement on polymer crystallization—the mechanism remains a controversial issue. This review will provide general guidance to designing and processing polymer materials with desired properties via a rational route of controlling the chain entanglement. [ABSTRACT FROM AUTHOR]

The nucleation efficiency (NE) of stereocomplex crystallites (SCs) formed in asymmetric poly(L‐lactide)/poly(D‐lactide) (PLLA/PDLA) blends is generally unsatisfactory because the competition between stereocomplexation and chain mixing involved in the melt‐mixing process can cause low formation efficiency and even severe aggregation of SCs. Herein, it is attempted to achieve high‐efficient formation of finely dispersed SCs particles by designing a unique melt‐mixing procedure, where the mixing of PLLA with 0.75 wt% PDLA is first performed at elevated temperatures (far above the melting temperature of SCs) to allow the homogeneous mixing of PLLA/PDLA chains and then at a low temperature (slightly above that of homocrystallites) to permit the full stereocomplexation of the premixed chains. It is found that the SCs formed in the blends exhibit unexpectedly low NEs (e.g., 54.5%), much inferior to that (73.6%) in the counterpart without undergoing premixing. This is because the introduction of premixing leads to a remarkable deterioration in the amount of SCs particles formed, despite decreased particle size, highlighting that the direct mixing at low temperatures of 170–180 °C (about 20–30 °C lower than that used in common melt‐processing of PLA) is more effective for the construction of SCs with superior NE. The mechanisms for these striking findings are discussed. [ABSTRACT FROM AUTHOR]

Toughening modification of poly(l‐lactide) (PLLA) with rubber particles is often realized at the cost of transparency, mechanical strength, and modulus because high rubber loadings are generally required for toughening. In this work, a promising strategy to simultaneously improve the transparency and stiffness–toughness performance of poly(butyl acrylate)‐poly(methyl methacrylate) (BAMMA) core‐shell rubber nanoparticles toughened PLLA blends by utilizing the stereocomplex (SC) crystallization between PLLA and poly(d‐lactide) (PDLA) is devised. The results reveal that the construction of SC crystallites in PLLA matrix via melt‐mixing PLLA/BAMMA blends with PDLA can prevent BAMMA nanoparticles from aggregation and promote them to form network‐like structure at lower contents. As a result, not only higher toughening efficiency with less rubber contents but also superior transparency is achieved in the PLLA/PDLA/BAMMA blends as compared with the PLLA/BAMMA ones where large aggregated BAMMA clusters are formed. Moreover, the outstanding reinforcement of SC crystallites network for PLLA can impart an enhanced tensile strength and modulus to PLLA/PDLA/BAMMA blends, thus improving the stiffness–toughness performance of PLLA/PDLA/BAMMA blends to a higher degree. This work demonstrates that SC crystallization is a promising solution to solve the contradiction between transparency and mechanical properties and then obtain superior comprehensive performances in rubber toughened PLLA blends. [ABSTRACT FROM AUTHOR]

There has been increasing interest in the use of bioactive glasses for soft and hard tissue regeneration due to their excellent ability in supporting angiogenesis and osteogenesis. Silicate 45S5 glass, discovered by Hench in 1969, remains as the "Gold Standard" in this material family. However, the ability to form 45S5 into complex 3D shapes is challenging due to its tendency to crystallize upon sintering. Another silicate 13‐93 glass shows better processing characteristics through viscous flow sintering. Our work attempts to provide a comprehensive understanding of the viscosity and crystallization kinetics on these two glasses and two intermediates between them (designated as 48S1T and 50S2T). Viscosity analysis reveals a low liquidus viscosity and a high fragility index for all four compositions, making it necessary to use a traditional sintering process to produce structures of desired, complex shape. Nonisothermal crystallization kinetics study using differential scanning calorimetry indicates that the two intermediates show better thermal stability than the 45S5 glass and approach that of 13‐93 glass. A gradual change in physical properties, thermal stability, and phase assemblage was noticed with the composition transitioning from 45S5 to 13‐93. Results from this work suggest the promising attributes in both intermediates 48S1T and 50S2T compositions, making them attractive candidates for further studies for wide biomedical applications. [ABSTRACT FROM AUTHOR]

Herein, we reported the formation mechanism of hybrid crystalline (cylindrite) in isotactic polypropylene (iPP)/carbon fiber (CF) via pulling a CF within the iPP melt. The α‐row nuclei layer closely attached to the surface of CF acts as a self‐nucleation site, rather than a heterogeneous nucleation one, to grow cylindrites. As a result, the polymorphic feature of iPP/CF cylindrite is significantly influenced by the microstructure of α‐row nuclei. With decreasing crystallization temperature (Tc), the polymorphic cylindrite changes from pure α‐form to mixed α‐/β‐form and to β‐rich form. The main characteristics of this change include: (a) the outlines of α‐row nuclei layer correspond to wave‐like, saw‐like, and straight lines; (b) the orientation level of iPP molecules in the α‐row nuclei layer become higher; (c) the α‐lamellae rearrange from loose to compact; and (d) the distance between the growth sites of β‐sectors and the surface of CF is evidently longer than in the case of α‐sectors. Moreover, this study provides a guideline for developing the interfacial enhanced iPP/CF composites through manipulation of polymorphic structure in cylindrites. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 368–377 The correlation between the α‐row nuclei and shear‐induced iPP/CF variable cylindrite (pure α‐cylindrite, mixed α/β‐cylindrite, and β‐rich cylindrite) was systematically established by comparing the detailed microstructure. The systematical growth processes of shear‐induced cylindrites with different crystalline temperatures are illustrated. Furthermore, it was concluded that the polymorphism of cylindrite is strongly dependent on the orientation and packing density of the fibril lamellae in the α‐row nuclei. [ABSTRACT FROM AUTHOR]

The preparation of multilayered structures has been thought as a complicated process until our recent study illustrating an effective method through high speed thin wall injection molding (HSTWIM) of polypropylene (PP) and polyethylene (PE) based blends. Current study investigates the effect of blends composition as well as the addition of carbon nanotubes (CNT) on the structure and properties of these blends. It is observed that a close ratio of high density polyethylene (HDPE) and impact copolymer polypropylene (ICP) triggers the formation of a multilayered structure. Meanwhile, PE is migrated into the rubber phase in ICP, leading to the distribution of some rubber phase on the interface between PP and PE, which is thought as beneficial for the interfacial interaction. Meanwhile, epitaxial growth of PE crystals on PP substrate is also observed. The presence of rubber phase on the interface, multilayered structure and epitaxial growth of PE crystals on PP are thought to be responsible for the observed mechanical enhancement in tensile strength as well as strain at break. Furthermore, the addition of CNTs leads to enhanced strength, reduced strain at break and anisotropic conductive network. [ABSTRACT FROM AUTHOR]

Abstract: Stereocomplex (SC) crystallization between poly( l‐lactide) (PLLA) and poly( d‐lactide) (PDLA) exhibits tremendous potential to improve the properties of polylactide (PLA), but the practical processing of SC‐type PLA (SC‐PLA) is significantly hindered by the insufficient melt stability and serious degradation after complete melting of SC crystallites over 240 °C. In a previous work, powder metallurgy inspired low‐temperature (180–210 °C) compression sintering is proposed to fabricate SC‐PLA products from its nascent powder. However, its industrial application is still challenging mainly due to the low production efficiency (half an hour is required) as well as the weak ability to fabricate products with complex shapes. In this work, an effort to rapidly fabricate complex‐shaped SC‐PLA products using low‐temperature injection molding technology is reported, where SC‐PLA nascent powder is partially melted. To ensure appropriate powder flowability, small amounts of glyceryl monostearate are incorporated as a lubricant. The results show that, both the self‐nucleation and flow‐induced nucleation effects facilitate the SC crystallization across the interfaces between adjacent unmelted powder particles, which considerably shortens the sintering cycle to about 2 min. In this way, complex‐shaped SC‐PLA products (such as gears) with superb performance are successfully fabricated by injection molding for the first time. [ABSTRACT FROM AUTHOR]

Neat grinding of 5-sulfosalicylic acid (A) and hexamethylenetetramine (B) yields two stoichiometric hydrated salts A1B1·H2O and A1B2·H2O. The hydrated forms A1B1·H2O and A1B2·H2O undergo a reversible solid state interconversion process with anhydrous A1B1 and A1B2 by getting or losing the water molecule. The interconversion between the stoichiometric variations of salts was investigated, in which the dynamic conversion can be obtained by adding one mole of one of the corresponding crystallizing components (A·2H2O or B) upon grinding. Furthermore, the four diverse forms of salts follow transformations reversibly in the solid state. All structural properties have been determined from X-ray diffraction, dynamic vapour sorption, and hot-stage microscopy analysis. The rationalization of the structural changes associated with the transformation has been discussed by combining with Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

The discovery of glass-ceramics, that is, the controlled crystallization of glass, by S. Donald Stookey was a mixture of serendipitous events involving both chance and exploratory research related to a practical concept. However, a combination of awareness of related literature, good observation skills, deductive reasoning, and a strong curiosity for exploratory work, was crucial for this chance event to bear fruit. As was the present case, a review of this story always stimulates new approaches for understanding of the fundamentals of crystallization and the design of glass-ceramics with improved properties. Two experiments of particular interest are presented in this paper. The first focuses on the change of viscosity of a specimen as a function of crystallization, while the second addresses the improvement of crack resistance by manipulating thermal history during crystallization. Our work reveals that glass-ceramic viscosity, that is, bulk viscosity during crystallization, is influenced by both temperature and phase assemblage. Further, as observed by Stookey, more than 60 years ago, high viscosity is important in controlling the shape of the final product. Finally, thermal history is shown to have a marked influence on the crack resistance of glass-ceramics. [ABSTRACT FROM AUTHOR]

ABSTRACT For polymer composites, interfacial crystalline structures retain an important role in the macroscopic properties and are significantly affected by the processing conditions, such as the temperature, time, and external field. In this study, the transcrystallization behavior of the carbon nanotube fiber and isotactic polypropylene composite was investigated by polarizing light microscopy. The influence of the formation of the transcrystalline layer on the interfacial adhesion was evaluated by a single-fiber fragmentation test. The results show that the growth rate of the transcrystalline layer was strongly influenced by the isothermal crystallization temperature, and the interfacial shear strength was markedly enhanced by the formation of the layer. The interfacial adhesion was further increased with the gradual perfection and growth of transcrystallinity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42119. [ABSTRACT FROM AUTHOR]

Poly(butylene succinate) (PBS) with different molecular weight was synthesized from 1, 4-butanediol and succinic acid by direct melt condensation. The synthesized PBS was identified by H-NMR and FTIR spectrometry. The molecular weight was calculated from the intrinsic viscosity, and its value was between 20000 and 70000. The crystallization behavior and crystal morphology as function of molecular weight were investigated by DSC and PLM, respectively. The mechanical properties and hydrolytic degradation behaviors related with change of molecular weight were also studied in this work. The results demonstrated that the properties of PBS were determined by both molecular weight and crystallization properties (crystallinity as well as crystal morphology). Our work is important for the design and preparation of PBS with proper molecular weight for its practical application. [ABSTRACT FROM AUTHOR]

Bioresource natural sisal fiber ( SF) was used to prepare single fiber-reinforced isotactic polypropylene ( iPP) composites. Three kinds of interfacial crystalline morphologies, spherulites, medium nuclei density transcrystallinity ( MD-TC) and high nuclei density transcrystallinity ( HD-TC), were obtained in the single fiber-reinforced composites by implementing quiescent or dynamic shear-enhanced crystallization and by modulating the compatibility interaction between SF and iPP. The development of interfacial shear strength ( IFSS) during the interfacial crystallization process was demonstrated for the first time using a combination of single-fiber fragmentation testing and optical microscope observation. A close correlation between IFSS and morphological characteristics of interfacial crystallization was well elucidated. The increases in IFSS were very different for spherulitic, MD-TC and HD-TC morphologies. The highest IFSS obtained was 28 MPa, after the formation of HD-TC, which was about 62% of the tensile strength of neat iPP (45 MPa). These results offer powerful and direct evidence that interfacial crystallization could play an important role in the enhancement of interfacial adhesion of real SF/ iPP composites. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this work, the synergistic effects of β-modification and impact polypropylene copolymer (IPC) on brittle-ductile (B-D) transition behavior of polypropylene random copolymer (PPR) have been investigated. It is interesting to find that adding both IPC and β-nucleating agent into PPR has three effects: (i) leading to a significant enhancement in β-crystallization capability of PPR, (ii) contributing to the shift of B-D transition to lower temperatures, (iii) increasing the B-D transition rate. The reason for these changes can be interpreted from the following two aspects. On one hand, the transition of crystalline structure from α-form to β-form reduces the plastic resistance of PPR matrix, thus causing the initiation of matrix shear yielding much easier during the impact process. On the other hand, the well dispersed rubbery phase in IPC with high molecular mobility at relatively low temperatures is beneficial to the shear yielding of PPR matrix and, subsequently, the great improvement in impact toughness of the ternary blends. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Nanohybrid shish kebab (NHSK) structure, in which fibrous carbon nanotubes (CNTs) act as shish, while polymer lamellae as kebab, is of particular interest both scientifically and technologically. In this work, two types of CNTs with the same diameter range and different topography structure, namely multiwalled carbon nanotubes (MWNTs) with a relatively smooth surface and double-walled carbon nanotubes (DWNTs) bundles with a groove structure, were used to induce polyethylene (PE) crystallization for the formation of NHSK. For PE/MWNTs system, NHSK was formed only at a relatively low crystallization temperature (Tc), and PE lamellae are not completely perpendicular to the long axis of MWNTs. However, for PE/DWNTs bundles system, NHSK could be obtained even at a much higher Tc, and almost all the PE lamellae are perpendicular to CNTs long axis, due to the unique "groove structure" formed by DWNTs bundles. The enhanced nucleation ability and the facilitated lamellae orientation by using DWNTs bundles are not only of great crystallography interest but also are very important for functional design in nanodevice applications. [ABSTRACT FROM AUTHOR]

Highly porous calcium phosphate (CaP) scaffolds for bone-tissue engineering were fabricated by combining a robocasting process with a sol-gel synthesis that mixed Calcium Nitrate Tetrahydrate and Triethyl Phosphite precursors in an aqueous medium. The resulting gels were used to print scaffolds by robocasting without the use of binder to increase the viscosity of the paste. X-ray diffraction analysis confirmed that the process yielded hydroxyapatite and β-tricalcium phosphate biphasic composite powders. Thus, the scaffold composition after crystallization of the amorphous structure could be easily modified by varying the initial Ca/P ratio during synthesis. The compressive strengths of the scaffolds are ~6 MPa, which is in the range of human cancellous bone (2-12 MPa). These highly porous scaffolds (~73 vol% porosity) are composed of macro-pores of ~260 μm in size; such porosity is expected to enable bone ingrowth into the scaffold for bone repair applications. The chemistry, porosity, and surface topography of such scaffolds can also be modified by the process parameters to favor bone formation. The studied sol-gel process can be used to coat these scaffolds by dip-coating, which induces a significant enhancement of mechanical properties. This can adjust scaffold properties such as composition and surface morphology, which consequently may improve their performances. [ABSTRACT FROM AUTHOR]

Interfacial interaction plays a key role in the preparation of high performance polymer composites. In this work, in order to explore the possibility to enhance the interfacial interaction via interfacial crystallization of polymer matrix onto the filler surface, interfacial crystallization structure and mechanical properties of linear low density polyethylene (LLDPE)/whisker composites were investigated. The composites were firstly prepared by melt compounding, followed by processing in both traditional and dynamic injection molding. DSC, WAXD, SEM were used to characterize the interfacial crystallization structure. And the mechanical properties were measured by tensile testing. An imperfect shish-calabash structure, with whisker served as shish, and irregular LLDPE spherulite as imperfect calabash, was formed during common injection molding processing. Such a structure was considered as the main reason for the strong interfacial adhesion and the obviously improved tensile strength and modulus. Furthermore, introducing shear could cause the formation of relatively perfect shish-calabash structure, leading to the stronger interfacial adhesion. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The effects of nucleating duality, imposed by a mixed nucleating agent (NA) system containing multi-walled carbon nanotubes (MWCNTs) and a rare earth (WBG), on the crystallization behaviors of isotactic polypropylene (iPP) including the peak temperature of crystallization ( T), polymorphic composition, and crystalline morphology, were probed in detail by calorimetry, X-ray diffraction, and polarized light microscopy. In such mixed nucleating agent system, MWCNTs is active filler to induce α-nucleation for iPP, while WBG serves as β-nucleating agent. When the WBG content was low (0.05%), the crystals of WBG were as a form of individual isotropic dendrite, and the enhancement of T was achieved by the incorporation of MWCNTs. As the WBG content was high as 0.1%, a percolated NA network consisted of needlelike crystals of WBG yielded before nucleating the prevalent crystallization of iPP. In this case, the addition of MWCNTs has no obvious effect on T. However, by varying the mass proportion of MWCNTs/WBG, the polymorphic composition was adjusted significantly, indicating a nucleation competition between MWCNTs and WBG. Although the competitive growth existed between α-crystals nucleated by MWCNTs and β-crystals nucleated by WBG, the formation of primary β-crystallite was always prior to the α-nucleated crystallization, as confirmed by crystalline morphology. These findings are useful for developing a new pathway to prepare iPP-based composite with good mechanical property via the addition of mixed nucleating system containing active inorganic filler and β-nucleating agent. [ABSTRACT FROM AUTHOR]

In this work, polyamide 66 (PA66) and its composites with multiwalled carbon nanotubes (MWNTs) were melt spun into fibers at different draw ratios. PA66 fibers at high draw ratio demonstrate a 40% increase in tensile strength, 66% increase in modulus and a considerable increase in toughness. It is demonstrated that this reinforcement can be mainly attributed to high-draw-ratio-induced good dispersion and orientation of MWNTs, particularly the enhanced interfacial adhesion between MWNT and matrix thanks to interfacial crystallization. Our work provides a simple but efficient method to achieve good dispersion and strong interfacial interaction through melt spinning. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The effect of clay on the nucleating behavior of 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS) in cryatallization of isotactic polypropylene ( iPP) was investigated by means of differential scanning calorimetry (DSC), dynamic rheology and polarized light microscopy (PLM). It is interesting to note that the incorporation of layered clay nanoparticles into DMDBS-nucleated iPP may induce a synergetic nucleation effect while the DMDBS content is below 0.1 wt%, otherwise it restricts the crystallization rate prominently as the DMDBS content increases up to 0.3 wt%, which has exceeded the content threshold to yield a nucleating agent (NA) network. As shown by dynamic rheological investigations, the clay nanoparticles demonstrate an obstructive effect of disturbing the consistency of DMDBS fibrils network. Moreover, to further demonstrate the importance of NA network formation in the crystallization of iPP, we used another NA named HPN-20e, which can not form network structure at all over the concentration studied, for comparison. In this case, the nucleated-crystallization rate is independent on the addition of clay nanoparticles, as the nucleating mechanism is an individual nuclei manner without NA network forming. [ABSTRACT FROM AUTHOR]

Special crystallization event of isotactic polypropylene (iPP) in a constrained environment, a layered clay network, was followed by in situ Fourier transform infrared (FTIR) spectroscopy during the cooling process. Before occurrence of nucleation/crystallization, a conformationally ordered phase, which consists of significant amounts of long 31 helices with 14 monomeric units, has been identified for the first time. More importantly, it was found that the long-ordering helices could play a more important role than short ones for the confined crystallization. It could be tentatively explained as due to the existence of constrained regions in the proximity of the nanoclay platelets or tactoids and the heterogeneous nucleation capability of the surface of nanoclay. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this work, as a part of a long-term project aimed at controlling of crystal structure and phase morphology for a injection molded product, we investigated the oriented structure and possible epitaxial growth of polyolefin blend (low-density polyethylene (LLDPE)/isotatic polypropylene (iPP)), achieved by dynamic packing injection molding, which introduced strong oscillatory shear on the gradually-cooled melt during the packing process. The crystalline and oriented structures of the prepared blends with different compositions were estimated in detail through 2D X-ray diffraction, calorimetry, and optical microscopy. As iPP was the dominant phase (its content was more than 50 wt%), our results indicated that it could be highly oriented in the blends. In such case, it was interesting to find that LLDPE epitaxially crystallized on the oriented iPP through a crystallographic matching between (100) and (010), resulting in an inclination of LLDPE chains, about 50° to the iPP chain axis. On the other hand, as iPP was the minor phase, iPP was less oriented and no epitaxial growth between iPP and LLDPE was observed; even LLDPE remained oriented. The composition-dependent epitaxial growth of LLDPE on oriented iPP could be understood as due to: (1) the effect of crystallization sequence, it was found that iPP always crystallized before LLDPE for all compositions; (2) the dependence of oriented iPP structure on the blend composition; (3) the 'mutual nucleation' between LLDPE and iPP due to their partial miscibility. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The introduction of carbon nanotubes in a polymer matrix can markedly improve its mechanical properties and electrical conductivity, and much effort has been devoted to achieve homogeneous dispersions of carbon nanotubes in various polymers. Our group previously performed successfully fluorine-grafted modification on the sidewalls of multi-walled carbon nanotubes (MWCNTs), using homemade equipment for CF4 plasma irradiation. As a continuation of our previous work, in the present study CF4 plasma-treated MWCNTs (F-MWCNTs) were used as a nanofiller with poly(ethylene terephthalate) (PET), which is a practical example of the application of such F-MWCNTs to prepare polyester/MWCNTs nanocomposites with ideal nanoscale structure and excellent properties. As confirmed from scanning electron microscopy observations, the F-MWCNTs could easily be homogeneously dispersed in the PET matrix during the in situ polymerization preparation process. It was found that a very low content of F-MWCNTs dramatically altered the crystallization behavior and mechanical properties of the nanocomposites. For example, a 15 °C increase in crystallization temperature was achieved by adding only 0.01 wt% F-MWCNTs, implying that the well-dispersed F-MWCNTs act as highly effective nucleating agents to initiate PET crystallization at high temperature. Meanwhile, an abnormal phenomenon was found in that the melt point of the nanocomposites is lower than that of the pure PET. The mechanism of the tailoring of the properties of PET resin by incorporation of F-MWCNTs is discussed, based on structure-property relationships. The good dispersion of the F-MWCNTs and strong interfacial interaction between matrix and nanofiller are responsible for the improvement in mechanical properties and high nucleating efficiency. The abnormal melting behavior is attributed to the recrystallization transition of PET occurring at the early stage of crystal melting being retarded on incorporation of F-MWCNTs. Copyright © 2009 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In order to prevent the properties, especially transparency, color and health security, of PET/clay nanocomposites from being deteriorated due to the thermal degradation of clay organo-modifer, we had directly modified sodium montmorillonite (Na+-MMT) with PET's monomer, bis (hydroxyethyl) terephthalate (BHET) which had a degradation temperature higher than 400°C, and successfully prepared the hybrids via in situ polymerization. Nanodispersion of clay and the intercalated morphology were determined, and compared with PET/Na+-MMT hybirds in which Na+-MMT was directly added without any treatment. Improved mechanical properties and Tg were observed for the prepared PET/ BHET-modified clay composites. More importantly, the film produced from the composites had the same transparency as that of pure PET even when 2 wt% of clay was added. Non-isothermal and isothermal crystallization experiments showed a very good neculation capability of the nano-dispersed clay, particularly at higher crystallization temperatures. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

CsLnMnSe3 (Ln = Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Y) and AYbZnQ3 (A = Rb, Cs; Q = S, Se, Te) have been synthesized from solid-state reactions at temperatures in excess 1173 K. These isostructural materials crystallize in the layered KZrCuS3 structure type in the orthorhombic space group Cmcm. The structure is composed of LnQ6 octahedra and MQ4 tetrahedra that share edges to form 2∞[LnMQ3] layers. These layers stack perpendicular to [010] and are separated by layers of face- and edge-sharing AQ8 bicapped trigonal prisms. There are no Q—Q bonds in the structure of the ALnMQ3 compounds so the formal oxidation states of A/Ln/M/Q are 1+/3+/2+/2−. The CsLnMnSe3 materials, with the exception of CsYbMnSe3, are Curie­Weiss paramagnets between 5 and 300 K. The magnetic susceptibility data for CsYbZnS3, RbYbZnSe3, and CsYbMSe3 (U = Mn, Zn) show a weak cusp at approximately 10 K and pronounced differences between field-cooled and zero-field-cooled data. However, CsYbZnSe3 is not an antiferromagnet because a neutron diffraction study indicates that CsYbZnSe3 shows neither long-range magnetic ordering nor a phase change between 4 and 295 K. Nor is the compound a spin glass because the transition at 10 K does not depend on ac frequency. The optical band gaps of the (010) and (001) crystal faces for CsYbMnSe3 are 1.60 and 1.59 eV, respectively; the optical band of the (010) crystal faces for CsYbZnS3 and RbYbZnSe3 are 2.61 and 2.07 eV, respectively. [ABSTRACT FROM AUTHOR]

Three new compounds, Cs2Bi2ZnS5, Cs2Bi2CdS5, and Cs2Bi2MnS5, have been synthesized from the respective elements and a reactive flux Cs2S3 at 973 K. The compounds are isostructural and crystallize in a new structure type in space group Pnma of the orthorhombic system with four formula units in cells of dimensions at 153 K of a=15.763(3), b=4.0965(9), c=18.197(4) A˚, V=1175.0(4) A˚3 for Cs2Bi2ZnS5; a=15.817(2), b=4.1782(6), c=18.473(3) A˚, V=1220.8(3) A˚3 for Cs2Bi2CdS5; and a=15.830(2), b=4.1515(5), c=18.372(2) A˚, V=1207.4(2) A˚3 for Cs2Bi2MnS5. The structure is composed of two-dimensional ∞2[Bi2MS52−] (M=Zn, Cd, Mn) layers that stack perpendicular to the [100] axis and are separated by Cs+ cations. The layers consist of edge-sharing ∞1[Bi2S66−] and ∞1[MS34−] chains built from BiS6 octahedral and MS4 tetrahedral units. Two crystallographically unique Cs atoms are coordinated to S atoms in octahedral and monocapped trigonal prismatic environments. The structure of Cs2Bi2MS5, is related to that of Na2ZrCu2S4 and those of the AMM′Q3 materials (A=alkali metal, M=rare-earth or Group 4 element, M′= Group 11 or 12 element, Q=chalcogen). First-principles theoretical calculations indicate that Cs2Bi2ZnS5 and Cs2Bi2CdS5 are semiconductors with indirect band gaps of 1.85 and 1.75 eV, respectively. The experimental band gap for Cs2Bi2CdS5 is &ap;1.7 eV, as derived from its optical absorption spectrum. [Copyright &y& Elsevier]

CsLnCdSe[sub 3] (Ln = Ce, Pr, Sm, Gd, Tb, Dy, Y) and CsLnHgSe[sub 3] (Ln = La, Ce, Pr, Nd, Sm, Gd, Y) have been synthesized at 1123 K. These isostructural materials crystallize in the layered KZrCuS[sub 3] structure type in the orthorhombic space group Cmcm and are group X extensions of the previously characterized Zn compounds. The structure is composed of two-dimensional [sup 2, sub ∞][LnMSe[sub 3]] layers that stack perpendicular to [010] and are separated by layers of face- and edge-sharing CsSe[sub 8] bicapped trigonal prisms. Because there are no Se-Se bonds in the structure of CsLnMSe[sub 3] (M = Zn, Cd, Hg), the formal oxidation states of Cs/Ln/M/Se are 1+/3+/2+/2-. CsSmHgSe[sub 3] does not adhere to the Curie-Weiss law, whereas CsCeHgSe[sub 3] and CsGdHgSe[sub 3] are Curie-Weiss paramagnets with µ[sub eff] values of 2.77 and 7.90 µ[sub B], corresponding well with the theoretical values of 2.54 and 7.94 µ[sub B] for Ce[sup 3+] and Gd[sup 3+], respectively. Single-crystal optical absorption measurements were performed with polarized light perpendicular to the (010) and (001) crystal faces of these materials. The band gaps of the (010) crystal faces range from 1.94 eV (CsCeHgSe[sub 3]) to 2.58 eV (CsYCdSe[sub 3]) whereas those of the (001) crystal faces span the range 2.37 eV (CsSmHgSe[sub 3]) to 2.54 eV (CsYCdSe[sub 3] and CsYHgSe[sub 3]). The largest band gap variation between crystal faces is 0.06 eV for CsYCdSe[sub 3]. Theoretical calculations for CsYMSe[sub 3] indicate that these materials are direct band gap semiconductors whose colors and optical band gaps are dependent upon the orbitals of Y, M, and Se. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) oligomer samples crystallized and annealed at high pressure were investigated with differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that better crystals were obtained through high-pressure crystallization from the melt than annealing under the same conditions. The difference of the effects of crystallization and annealing on the morphology of crystals reduced with the increase of crystallization time. The melting temperature was determined by the lamellar thickness when it was shorter than the length of the molecular chains, while the main factor governing the melting temperature changed from lamellar thickness to density of chain-end defects when the lamellar thickness was much longer than the molecular length. PET oligomer extended-chain crystals with thickness up 100 μm were obtained. [ABSTRACT FROM AUTHOR]

Three commercial metallocene-catalyst synthesized short-chain branched polyethylene (SCBPE) samples with similar molecular weights and molecular weight distributions were investigated in terms of their molecular structural (comonomer sequences and compositions) inhomogeneity and crystal morphology. Two of these samples [SCBPE(B1) and SCBPE(B2)] contained different ratios of a butene comonomer (20.7 and 26.8 SCB/1000 carbons, respectively), while the third sample, SCBPE(H), contained a branched hexane comonomer (7.8 SCB/1000 carbons). A linear PE fraction was also investigated for comparison. Differential scanning calorimetry (DSC) results indicate that multiple-step isothermal (thermal segregation) experiments lead to multiple endothermic melting processes in these SCBPEs during heating, a phenomenon that was not observed in the linear PE. Wide-angle X-ray diffraction (WAXD) experiments show that all of these SCBPEs possess an orthorhombic crystal lattice with different crystallinities. Linear coefficients of thermal expansion along both the a- and b-axes of the PE crystals were also determined using WAXD at different temperatures. This lateral lattice expansion is critically associated with the comonomer size and composition ratio of the SCB series. Small-angle X-ray (SAXS) scattering results of the thermal segregated samples obtained during heating required a differential scattering data treatment. It was found that the long period for each isothermal crystallization step was different and increased with increasing temperature. By increasing the comonomer composition at a constant temperature, the long period was also increased, although the thickness of the crystal lamellae decreased. This was due to an increase of the noncrystalline layer thickness between two neighboring lamellae. The crystalline morphology was observed under transmission electron microscopy (TEM). During multiple-step isothermal crystallization, the crystalline morphology exhibited a... [ABSTRACT FROM AUTHOR]

Oligocene and Miocene Himalayan anatexis is generally thought to have been induced by intracrustal heating or processes without the involvement of mantle-derived heat and materials, suggesting that the Himalayan leucogranites are typical examples of purely crustal melts. This study focuses on a Miocene leucogranite at Langkazi within the Himalayan orogen, an intrusion that contains a large number of dioritic enclaves. These enclaves have typical igneous textures, contain acicular apatites, and have back-veining structures, quenched margins, and crystallization ages identical to the hosting two-mica granites, indicating that these enclaves are magmatic. Although the enclaves are evolved, the most primitive samples contain high concentrations of MgO (up to 4.3 wt.%), Cr (up to 159 ppm), and Ni (up to 102 ppm), are strongly enriched in large-ion lithophile elements, are depleted in high-field-strength elements, have negative ε Nd(t) values (–8.6 to –6.1), and have relatively high 87 Sr/ 86 Sr (i) values (0.7085–0.7137), suggesting that they were derived from a relatively enriched region of the lithospheric mantle source. Whole-rock geochemical data indicate that the hosting Langkazi leucogranite formed from magmas generated by the partial melting of metapelite material within the High Himalaya crystalline sequence, and these magmas subsequently mixed with mantle-derived melts that are now represented by the Langkazi dioritic enclaves. This indicates that mantle-derived material played an important role in the generation of the Langkazi intrusions. The whole-rock geochemical compositions of samples from the study area also indicate that the primary melts that formed the Langkazi enclaves were significantly contaminated by the relatively juvenile Himalayan lower crustal material, suggesting in turn that these mantle-derived magmas underwent MASH (crustal melting, melt assimilation, magma storage, and homogenization) processes at the base of crust, introducing heat to the lower crust. This mantle-derived heat may have induced partial melting of the Himalayan lower crust, forming adakite-like magmas. Although the small volumes of these dioritic enclaves suggest that this heat may have assisted the genesis of the north Himalayan granites and the High Himalayan leucogranites, whereas in situ crustal radiogenic heating, shear heating, and decompression melting dominated the melting processes in this region. [ABSTRACT FROM AUTHOR]

The solvent-shift strategy was used to identify appropriate polymers that inhibit humidity-induced solid-state crystallization of amorphous solid dispersions (ASDs). Lacidipine with the polymers, PVP-K30, HPMC-E5 or Soluplus, were combined to form amorphous solid dispersions prepared by solvent evaporation. The formulations were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier-transform infrared spectroscopy (FT-IR) and were subjected to in vitro dissolution testing. The moisture had a significant impact on the amount dissolved for the solid dispersions. Molecular docking studies established that hydrogen bonding was critical for the stabilization of the solid dispersions. The rank order of the binding energy of the drug–polymer association was Soluplus (−6.21 kcal/mol) > HPMC-E5 (−3.21 kcal/mol) > PVP-K30 (−2.31 kcal/mol). PVP-K30 had the highest water uptake among the polymers, as did ASD system of lacidipine-PVP-K30 ASDs. In the Soluplus ASDs, with its strong drug–polymer interactions and low water uptake, moisture-induced solid-state crystallization was not observed. [ABSTRACT FROM AUTHOR]

Rigid inorganic filler has been long time used as a reinforcement agent for polymer materials. Recently, more work is focused on the possibility that using filler as a compatibilizer for immiscible polymer blends. In this article, we reported our efforts on the change of phase morphology and properties of immiscible polypropylene(PP)/polystyrene(PS) blends compatibilized with nano-SiO2 particles. The effects of filler content and mixing time on the phase morphology, crystallization behavior, rheology, and mechanical properties were investigated by SEM, DSC, ARES and mechanical test. A drastic reduction of PS phase size and a very homogeneous size distribution were observed by introducing nano-SiO2 particles in the blends at short mixing time. However, at longer mixing time an increase of PS size was seen again, indicating a kinetics-controlled compatibilization. This conclusion was further supported by the unchanged glass transition temperature of PS and by increased viscosity in the blends after adding nano-SiO2 particles. The compatibilization mechanism of nano-SiO2 particles in PP/PS blends was proposed based on kinetics consideration. [Copyright &y& Elsevier]

The AnMnSe3 (An=Th, U) compounds were synthesized from high-temperature solid-state reactions of the constituent elements at 1223 and 1273 K, respectively. Both compounds are isostructural with UFeS3 and crystallize in the space group Cmcm of the orthorhombic system with four formula units in a cell. Cell constants (A˚) at 153 K are: ThMnSe3, 4.0304(4), 12.795(1), 9.2883(9); UMnSe3, 3.931(5), 12.705(14), 9.148(10). The structure comprises layers of MnSe6 octahedra that alternate with layers of AnSe8 bicapped trigonal prisms along the b-axis. Because there are no Se–Se bonds in the structure of AnMnSe3 the formal oxidation states of An/Mn/Se are 4+/2+/2−. UMnSe3 is a ferromagnet with TC=62 K. [Copyright &y& Elsevier]

As a bio-based polymer with excellent mechanical properties, good biodegradability and biocompatibility, polylactic acid (PLA) displays considerable potential to replace traditional petrochemical-based polymers for application. However, poor toughness and heat resistance restrict its wide application. In this work, PLA based PLA/PBAT blends with excellent comprehensive performance were prepared through the synergistic effect of high mold temperature as well as strong shear field. SEM, DSC and WAXD were conducted to characterize the crystal and micro-morphology of the samples. The results show that highly oriented shish-kebab and hybrid shish-kebab structures are observed in VIM-H sample. The crystallinity increases dramatically, which can reach 48%. Besides, the toughness, strength and heat resistance of VIM-H all markedly improve. The Vicat softening temperature (VST) reaches up to 149.2 °C, while the tensile strength and impact strength increase to 89.07 MPa and 10.36 kJ/m2, respectively. This study proves the synergistic enhancement of the properties for PLA/PBAT blends by high mold temperature as well as strong shear field, which provides a new method to obtain high-performance PLA materials and is beneficial for the wider application of PLA products. [Display omitted] • Shish-kebab and hybrid shish-kebab structures can be observed in VIM-H sample. • The crystallinity of the blends increases significantly. • Products with good comprehensive performance were obtained. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is the most important biopolymer material due to its excellent biocompatibility, biodegradability, and processability. However, its widespread applications were significantly limited by its low crystallization rate. While adding small molecule organic nucleating agents became a commonly used method in enhancing the crystallization rate, these nucleating agents generally suffer from limited solubility, which caused compromised nucleation efficiency and undesirable product appearance due to their precipitation onto the surface of the PLA products overtime. Here we report an efficient method for improving the PLA crystallization performance by using polyethylene (PE) ionomer as an additive in the PLA/TMC300 (an organic nucleating agent) nucleation/crystallization process. The added ionomer led to enhanced crystallization rate and reduced crystalline grain size. The resulting PLA from crystallization with TMC300 and ionomer showed reduced glass transition temperatures, reduced contact angles, and enhanced elastic modulus without compromising the impact strength and elongation at break. A possible mechanism was proposed for the remarkable synergistic effects of ionomer and TMC-300 in modifying the PLA crystallization process with the ionomer playing the roles of both plasticizer (enhanced PLA chain mobility and crystallization rate) and compatibilizer (enhanced dissolution and dispersion of TMC300 in the PLA matrix). This work offered a promising strategy for crystallization and modification of PLA materials. [Display omitted] • Polyethylene (PE) ionomer is used as an additive to enhance PLA crystallization. • The ionomer loading is very small compared to conventional plasticizers. • The ionomer and TMC-300 show significant synergistic effects in enhancing the crystallization of PLA, and the ionomer acts as both a plasticizer and a compatibilizer. • The ionomer accelerates crystallization while reducing the grain size, which reduces the negative impact of nucleating agents on the properties of PLA. [ABSTRACT FROM AUTHOR]

Polyphenylene sulfide (PPS) has a prospective application in high-frequency communication due to its excellent dielectric properties. However, owing to the strong melt memory effect, the crystalline structure of PPS is very sensitive to the processing conditions and difficult to be controlled. To date, the melt memory effect of polymer cannot be detected directly and quantitatively. In this work, four PPS samples were successively prepared via polymerization, extrusion and dissolution treatment. The Fourier infrared transform spectroscopy (FTIR), high-temperature gel permeation chromatography (HT-GPC) and dynamic rheological tests disclose that these four PPS samples have analogous molecular structure and only differ in entanglement density. The molecular weight between entanglements (M e) decreases gradually from 1188 to 354 g/mol. Furthermore, differential scanning calorimetry (DSC) and polarized optical microscopy (POM) measurements were carried out to study the effect of entanglement density on the crystallization kinetics of PPS. It is found that entanglement density is a key indicator to characterize the melt memory effect of PPS semi-quantitatively, and the residual local ordered structures in PPS melt is proportional to M e. In addition, the crystallization kinetics of PPS is determined by the cooperation of melt memory effect (nucleation) and entanglement density (growth). Accordingly, the relationship of "chain entanglements" → "melt memory effect" → "crystallization behavior" of PPS is established, constructing a roadmap for the precise control of crystalline structures of PPS products during practical processing. Diagram of the relationship of "chain entanglements" → "melt memory effect" → "crystallization behavior" of PPS. [Display omitted] • Entanglement density of PPS was controlled by different methods (1188-354 g/mol). • Entanglement density can be used to characterize the memory effect of PPS. • Memory effect and entanglement together affect the crystallization kinetics of PPS. [ABSTRACT FROM AUTHOR]