The influence of core-shell structured modifiers on the toughness of poly (vinyl chloride)

The core-shell structured grafted copolymer particles of polybutadiene grafted polymethyl methacrylate (PB-g-PMMA, MB) were prepared by emulsion polymerization. The MB particles were used to modify poly (vinyl chloride) (PVC) by melt blending. The mechanical properties of the PVC blends were investigated. The micro-morphology of the PVC blends was observed by scanning electron microscopy (SEM). The results indicated that the samples with the best impact strength could be obtained when the core-shell weight ratio of PB to PMMA is lower than 93:7, the mechanical properties correlated well with SEM morphologies, the addition of modifier with the ratio core to shell of 93:7 could reduce the domain size of the dispersed phase. Furthermore, the compatibility and properties of the blends were greatly enhanced and improved. The modifier particles could be well dispersed in the PVC matrix.     

Silicone‐based impact modifiers for poly(vinyl chloride), engineering resins,and blends

Silicone‐based impact modifiers were prepared in a previous study. The modifiers were composed of silicone/acrylic rubber cores and grafted acrylic shells. They improved the toughness of poly(vinyl chloride) (PVC) and poly(methyl methacrylate). The silicone emulsion that was used to produce the silicone‐based impact modifiers was prepared via two routes: emulsion polymerization and bulk polymerization of octamethyltetracyclosiloxane. Many silicone‐based impact modifiers were produced that had different silicone/acrylic rubber characteristics. Through a toughness examination of modified PVC, the best composition of the silicone‐based impact modifiers was obtained, and the silicone content in the rubber composition was 25 wt %. The morphology of the silicone‐based impact modifiers, determined by transmission electron microscopy, was as follows: core and second shell polymers were mainly poly(butyl acrylate), and the first shell polymer was silicone. The silicone‐based impact modifiers were blended with engineering resins such as PVC, polycarbonate (PC), poly(butylene terephthalate) (PBT), and PC/PBT mixtures. The impact strength under standard conditions and after weathering test conditions for blends of the silicone‐based impact modifiers were investigated with respect to two commercially available acrylic and methyl methacrylate/butadiene/styrene impact modifiers. The results showed good weatherability and good toughness under low‐temperature conditions for the silicone‐based impact modifiers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1112–1119, 2004     

Miscibility and properties of poly(l-lactic acid)/poly(butylene terephthalate) blends

Binary blends of poly(l-lactide) (PLLA) and poly(butylene terephthalate) (PBT) containing PLLA as major component were prepared by melt mixing. The two polymers are immiscible, but display compatibility, probably due to the establishment of interactions between the functional groups of the two polyesters upon melt mixing. Electron microscopy analysis revealed that in the blends containing up to 20% of poly(butylene terephthalate), PBT particles are finely dispersed within the PLLA matrix, with a good adhesion between the phases. The PLLA/PBT 60/40 blend presents a co-continuous multi-level morphology, where PLLA domains, containing dispersed PBT units, are embedded in a PBT matrix. The varied morphology affects the mechanical properties of the material, as the 60/40 blend displays a largely enhanced resistance to elongation, compared to the blends with lower PBT content.     

Preparation of core‐shell structured particle and its application in toughening PA6/PBT blends

Combining the excellent mechanical strengths of polyamide 6 (PA6) with the low water absorption of poly(butylene terephthalate) (PBT) was supposed to be a feasible way to prepare a high comprehensive performance material. However, the poor compatibility between PA6 and PBT resulted in low‐notched impact strength of PA6/PBT blends. Poly(n‐butyl acrylate)/poly(methyl methacrylate‐co‐methacrylic acid) (PBMMA), a core‐shell structured modifier with controlled particle sizes, was prepared by seed emulsion polymerization and confirmed by Transmission electron microscope (TEM). The PBMMA particles as toughening modifier and compatilizer were employed to toughen PA6/PBT blends. The notched impact strength of the PA6/PBT blends was significantly increased and the water absorption was reduced with the addition of PBMMA particles. With 23.0 wt% modifier loading, the notched impact strength of the blends was 25.66 kJ/m², which was 4.04 times higher than that of pure PA6/PBT. Meanwhile, the water absorption of the blends was only 1.3%, dropping 53.6% compared with pure PA6 and reducing by 26.6% than PA6/PBT. Scanning electron microscope results showed that the PBMMA particles were dispersed in the PA6/PBT blends homogeneously, and the toughening mechanism was the cavitation of rubber particles and shear yielding of the matrix. Thermo‐gravimetric analysis analysis demonstrated that the compatibility between PA6 and PBT was improved with the addition of core‐shell PBMMA particles. The core‐shell particles could be used as an effective modifier to achieve the high toughness and low water absorption for PA6/PBT blends. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of Zinc oxide nanoparticles on the morphology and viscoelastic properties of polyamide 6/poly(butylene terephthalate) blends

The morphology of polyamide 6/poly(butylene terephthalate)(PA6/PBT, 70/30, W/W) blends filled with pristine Zinc oxide(ZnO) nanoparticles and ZnO surface-modified by γ-glycidoxypropyltrimethoxysilane(K-ZnO) was investigated. The incorporation of ZnO and K-ZnO by one-step compounding both resulted in a smaller size and narrower distribution of PBT domains and the effect of ZnO was greater than K-ZnO. To reveal the underlying mechanism, two-step compounding in which ZnO or K-ZnO was premixed with PA6 or PBT was conducted and the finest morphology was achieved when mixing PA6 with premixed PBT/ZnO. Transmission electron microscopy(TEM) demonstrated that ZnO was distributed in PBT in all cases and K-ZnO was enriched at the interface except when K-ZnO was premixed with PBT. ZnO and K-ZnO caused a deterioration in the melt rheological properties of PBT, which played a dominating role in the morphological changes. In addition, the interfacial localization of K-ZnO enhanced the dynamic rheological properties of PA6/PBT blends substantially.     

The impact of resorcinol bis(diphenyl phosphate) and poly(phenylene ether) on flame retardancy of PC/PBT blends

Flame retardancy of bisphenol A polycarbonate (PC)/poly(butylene terephthalate) (PBT) blends was improved by the addition of resorcinol bis(diphenyl phosphate) (RDP) and poly(phenylene ether) (PPO). A PC/PBT blend at 70/30 weight ratio obtained a V‐0 rating by the addition of 10 wt% RDP and 10 wt% PPO. The combination of 5 wt% methyl methacrylate‐butadiene‐styrene tercopolymer (MBS) with 3 wt% ethylene‐butylacrylate‐glycidyl methacrylate tercopolymer (PTW) causes a remarkable increase in toughness of the PC/PBT/RDP blend while maintaining a high rigidity. A detailed investigation of the flame‐retardant action of PC/PBT/RDP and PC/PBT/RDP/PPO blends was performed using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), TGA‐FTIR, temperature‐programmed pyrolysis/gas chromatography/mass spectrometry (TPPy/GC/MS), and scanning electron microscopy/energy dispersive spectrometer (SEM/EDS). The results demonstrate that RDP induces a higher char yield at ca. 450 °C and synchronously increases the thermal stability of the blend with PPO. The flame‐retardant role of RDP in the condensed phase was discerned from TGA, FTIR, and SEM/EDS of the residues. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of polyacrylate core-shell structure latex by radiation techniques

A series of poly(butyl acrylate-co-methyl methacrylate)/poly (ethyl acrylate-co-acrylic acid) interpenetrating polymer network (IPN) was synthesized in latex form by emulsion polymerization. The multiphase morphology of the latex particles was studied after two-stage polymerization by using transimission electron microscope (TEM), the result indicated that the morphology of the particles comprises gradient shell structure, cellular structure and core-shell structure. The change of morphology might stem from emulsion polymerization by radiation initiation or chemical initiation and the weight composition of poly(EA-co-MMA) seed latex which formed the core. By radiation techniques, we successfully synthesized poly( BA-co-MMA)/poly(EA-co-AA) latex of core-shell structure having (42-8)/(46-4) weight compositions. The PA core-shell structure latex applied to textile as a water proofing coating showed higher water-pressure and easier handling than that with PA homogeneous phase structure latex.     

Morphology and Mechanical Properties of Nylon 6/PBT Blends Compatibilized with Styrene/Maleic Anhydride Copolymer

The mechanical properties and dynamic mechanical properties of blends composed of Nylon 6 and poly(butylenes terephthalate)(PBT),with styrene/maleic anhydride(SMA)as compatibilizer,were studied.The observation on the morphologies of the etched surfaces of the cryogenically fractured specimens via scanning electron microscopy(SEM)demonstrated that in the compatibilized Nylon 6/PBT blends,there exists a finer and more uniform dispersion induced by the in-situ interfacial chemical reactions during the preparation than that in the corresponding uncompatibilized blends.On the other hand,the overall mechanical properties of the compatibilized blends could be remarkably improved compared with those of the uncompatibilized ones.Moreover,increasing the amount of the compatibilizer SMA leads to a more efficient dispersion of the PBT phase in Nylon 6/PBT blends.Furthermore,there exists an optimum level of SMA added to achieve the maximum mechanical properties.As far as the mechanism of this reactive compatibilization is concerned,the enhanced interfacial adhesion is necessary to obtain improved dispersion,stable phase morphology,and better mechanical properties.     

Synthesis and characterization of a novel silane-based vinylic monomer and its application in the multilayer core-shell latex

A novel monomer methacrylamidophenoxy dimethylsiloxy phenylphthalimide was obtained by a reaction of 4,4′-bis-aminophenoxy dimethylsilane, phthalic anhydride and methacryloyl chloride. Then it has been used in the synthesis of phase-separated polymer latex with a multilayer core-shell morphology by surface cross-linking emulsion polymerization. Poly(butyl acrylate) was used for the seed and the core of the latex, the inner shell was poly(butyl acrylate/styrene) cross-linked with divinylbenzene to avoid phase inversion, and the poly(methyl methacrylate/butyl acrylate/methacrylamidophenoxy dimethylsiloxy phenylphthalimide) was the outer shell. The structural elucidation of monomer was carried out by elemental analysis, FTIR, ¹H NMR, and ¹³C NMR spectroscopic techniques. The morphology and glass transition temperatures of the synthesized product were investigated by transmission electron microscopy and differential scanning calorimetry, respectively. The multilayer core-shell structure was clearly shown in TEM micrographs, and the three-phase separation was confirmed by DSC analysis. The obtained results demonstrated that the average particle size is 81.8, 108 and 132 nm for the core, core-shell and multilayer core-shell particles, which agrees with the TEM micrograph measurement of 75, 103, and 131 nm, respectively.     

New super‐tough poly(butylene terephthalate) materials based on compatibilized blends with metallocenic poly(ethylene‐octene) copolymer

New super‐tough poly(butylene terephthalate) (PBT)/poly(ethylene‐octene) copolymer (PEO) blends containing 2 wt% poly(ethylene‐co‐glycidyl methacrylate) (EGMA) as a compatibilizer were obtained by extrusion and injection molding. The blends comprised of an amorphous PBT‐rich phase with some miscibilized EGMA, a pure PEO amorphous phase, and a crystalline PBT phase that was not influenced by the presence of either PEO or EGMA. The blends showed a fine particle size up to 20 wt% PEO content. Super‐tough blends were obtained with PEO contents equal to or higher than 10%. The maximum toughness was very high (above 710 J/m) and was attained with 20% PEO without chemical modification of the commercial components used. Copyright © 2003 John Wiley & Sons, Ltd.     

Toughening of polyvinylchloride by core-shell rubber particles: Influence of the internal structure of core-shell particles

The work focused on the influence of the internal structure of MBS core-shell impact modifiers on the properties of PVC/MBS blends. MBS was synthesized by grafting styrene and methyl methacrylate onto PB seed latex by emulsion polymerization. Different monomer feeding manners and initiators were employed to control the internal structure of core-shell particles. The investigation of the morphology of MBS showed that when styrene monomer was fed in a semicontinuous feeding manner and redox initiator was used, core-shell particles with rarely sub-inclusions could be obtained. When preswollen manner of styrene monomer and redox initiator were employed, there were a large number of small sub-inclusions in the core of MBS. When AIBN was used as initiator, large sub-inclusions could be found in the core of MBS. The results of the Izod impact tests showed that PVC/MBS blend with MBS prepared by preswollen manner had the lowest brittle-ductile transition temperature. And TEM showed that the different internal structures of core-shell particles could lead to different deformation mechanisms. While the results of transparency tests showed that the presence of the sub-inclusions in the MBS impaired the transparency of the blends.     

Morphology of poly(butylene terephthalate)–poly(ethylene terephthalate‐co‐isophthalate‐co‐sebacate) segmented copolyesters

Segmented copolyesters, namely, poly(butylene terephthalate)–poly(ethylene terephthalate‐co‐isophthalate‐co‐sebacate) (PBT‐PETIS), were synthesized with the melting transesterification processing in vacuo condition involving bulk polyester produced on a large scale (PBT) and ternary amorphous random copolyester (PETIS). Investigations on the morphology of segmented copolyesters were undertaken. The two‐phase morphology model was confirmed by transmission electron microscopy and dynamic mechanical thermal analysis. One of the phases was composed of crystallizable PBT, and the other was a homogeneous mixture of PETIS and noncrystallizable PBT. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2257–2263, 2003     

Electrical conductivities of carbon nanotube-filled polycarbonate/polyester blends

Carbon nanotube (CNT)-filled polycarbonate (PC)/poly(butylene terephthalate) (PBT) and polycarbonate (PC)/poly(ethylene terephthalate) (PET) blends containing 1 wt% CNTs over a wide range of blend compositions were prepared by melt mixing in a torque rheometer to investigate the structure-electrical conductivity relationship. Field emission scanning electron microscopy was used to observe the blend morphology and the distribution of CNTs. The latter was compared with the thermodynamic predictions through the calculation of wetting coefficients. It was found that CNTs are selectively localized in the polyester phase and conductive blends can be obtained over the whole composition range (20 wt%, 50 wt% and 80 wt% PBT) for CNT-filled PC/PBT blends, while conductive CNT-filled PC/PET blends can only be obtained when PET is the continuous phase (50 wt%, 80 wt% PET). The dramatic difference in the electrical conductivity between the two types of CNT-filled PC/polyester blends at a low polyester content (20 wt%) was explained by the size difference of the dispersed phases on the basis of the transmission electron microscope micrographs.     

三元乙丙橡胶环氧化增韧聚对苯二甲酸丁二酯的研究

三元乙丙橡胶环氧化增韧聚对苯二甲酸丁二酯的研究王学会，张会轩，王新华，王志刚，蒋俊光，姜炳政（吉林工学院化工系，长春，１３００１２）（中国科学院长春应用化学研究所）关键词三元乙丙橡胶，环氧化，ＰＢＴ，增韧作用，共混物聚对苯二甲酸丁二酯（ＰＢＴ）具有优...     

Compatibilization of PBT/PP Blends by Adding Side-chain Liquid Crystalline Ionomer with Quaternary Pyridinium Groups

A side-chain liquid crystalline ionomer(SLCI) was synthesized by grafting copolymerization of 4-(4-ethoxybenzoyloxy)-4′-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blended with polypropylene(PP) and polybutylene terephthalate(PBT) by melt mixing. The thermal behavior, liquid crystalline properties, morphological structure, and mechanical properties of the blends were investigated by differential scanning calorimetry(DSC), polarizing optical microscopy(POM), scannin...     

MELT BLENDS OF POLY (BUTYLEN TEREPHTHALATE) AND A THERMOTROPIC LIQUID CRYSTALLINE POLYMER

With the help of differential scanning calorimetry, cone-plate and capillary rheometry andscanning electron microscopy, a research has been conducted on rheological behavior,crystallization and morphology of poly (butylene terephthalate) (PBT) blends containing athermotropic LCP. The blend has zero entrance pressure loss, although the LCP has rather largeone. The viscosity curve of the blend lies between those of the LCP and PBT. The crystallizationof PBT is not affected by the presence of the LCP together with no indication oftransesterification between the two ingredients. LCP spheres and ellipsoids with the size of 0. 5--1. 5 μm disperse in PBT matrix uniformly, which is related to the viscosity ratio of the twocomponents.     

Synthesis of titania/polymer core-shell hybrid microspheres

Monodisperse titania/polymer core-shell microspheres were prepared by a two-stage reaction with titania as core and poly(ethyleneglycol dimethacrylate) (PEGDMA) as shell, in which the titania cores were synthesized by a sol-gel method and subsequently grafted with 3-trimethoxysilyl methacrylate as the first-stage reaction to incorporate the vinyl groups on the surface of inorganic core. The PEGDMA shell was then encapsulated over the MPS-modified titania core by distillation precipitation polymerization of ethyleneglycol dimethacrylate in neat acetonitrile during the second-stage polymerization via capture of the radicals of EGDMA with the aid of the reactive vinyl groups on the surface of inorganic core without any stabilizer or surfactant. The shell thickness of the core-shell hybrid microspheres was controlled by the feed of EGDMA monomer during the polymerization. The resultant titania particles and core-shell microspheres were studied by transmission electron microscopy, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, and thermogravimetric analysis.     

Determination and comparison of the essentialwork of fracture (EWF) of two polyester blends

The fracture toughness of blends of polypropylene terephthalate (PPT) with polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) were investigated. Binary blends were prepared comprising 10:90, 30:70, 50:50, 70:30 and 90:10 mass/mass%. The fracture toughness was determined for each blend using the essential work of fracture (EWF) method and thin film double edge notched tension (DENT) specimens. The specific essential work of fracture, w _e, values obtained for blends of PET/PPT ranged from 27.33 to 37.38 kJ m^–2 whilst PBT/PPT blends yielded values ranging from 41.78 to 64.23 kJ m^–2. Differential scanning calorimetry (DSC) was employed to assess whether or not crystallinity levels influence the mechanical properties evaluated. The fracture toughness of PPT deteriorated with PET incorporation. However, high we values exceeding that of pure PPT were obtained for PBT/PPT blends across the composition range studied.     

Tough and multi-responsive hydrogels based on core-shell structured macro-crosslinkers

Novel hydrogels based on core-shell structured macro-crosslinkers were synthesized,which exhibited high toughness and multiple responsiveness.Sodium dodecyl sulfate (SDS) micelles mediated by NaC1 were used to encapsulate hydrophobic stearyl methacrylate (C18) in the core,and hydrophilic 2-acrylamido-2-methyl-1-propanesulfonic (AMPS)monomers in the corona.Such core-shell micelles were simultaneously copolymerized with acrylamide monomers through free radical polymerization.As a result,hydrogels crosslinked by amphiphilic "poly(C 18)-PAMPS" macro-crosslinkers were obtained.These hydrogels showed excellent tensile and compression strength and toughness.Cyclic compression loadingunloading tests demonstrated that the hydrogels were of outstanding fatigue resistance,and showed partial damage of energy dissipation mechanism.The damaged energy dissipation mechanism could be recovered at room temperature and the recovery could be accelerated at elevated temperatures.The hydrogels were sensitive to the change in pH and ion strength,showing reversible swelling/deswelling behaviors.     

Effect of poly(vinyl acetate) (PVAc) on thermal behavior and mechanical properties of poly(3-hydroxybutyrate)/poly(propylene carbonate) (PHB/PPC) blends

To assess the compatibility of blends of synthetic poly(propylene carbonate) (PPC), with a natural bacterial poly(3-hydroxybutyrate) (PHB), a simple casting procedure of blend was used. poly(3-hydroxybutyrate)/poly(propylene carbonate) blends are found to be incompatible according to DSC and DMA analysis. In order to improve the compatibility and mechanical properties of PHB/PPC blends, poly(vinyl acetate) (PVAc) was added as a compatibilizer. The effects of PVAc on the thermal behavior, morphology, and mechanical properties of 70PHB/30PPC blend were investigated. The results show that the melting point and the crystallization temperature of PHB in blends decrease with the increase of PVAc content in blends, the loss factor changes from two separate peaks of 70PHB/30PPC blend to one peak of 70PHB/30PPC/12PVAc blend. It is also found that adding PVAc into 70PHB/30PPC blend can decrease the size of dispersed phase from morphology analysis. The result of tensile properties shows that PVAc can increase the tensile strength and Young’s modulus of 70PHB/30PPC blend, and both the elongation at break and the tensile toughness increase significantly with PVAc added into 70PHB/30PPC.