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1.
Encapsulated nanometer calcium carbonate (nano‐CaCO3) was prepared using styrene and maleic anhydride (MAH) copolymer in 2‐propanol or methanol–water mixture in the presence of different initiator systems. The particle morphology and physical properties of the encapsulated nano‐CaCO3 particles, such as the interaction between the encapsulating polymer and the nano‐CaCO3, and the thermal stability of encapsulated nano‐CaCO3 were studied by Fourier‐transform infrared spectroscopy (FTIR), Soxhlet extraction experiments, thermogravimetric analysis banded with FTIR (TGA‐FTIR) and transmission electron microscopy (TEM). The encapsulating ratio and the stable encapsulating ratio of encapsulated nano‐CaCO3 were characterized. The results showed that a strong interfacial interaction was obtained due to the formation of a chemical bond or ion‐dipole between the C?O group of MAH and Ca2+ ion of nano‐CaCO3. The encapsulating ratio and stable encapsulating ratio of nano‐CaCO3 initiated by AIBN was higher than that initiated by BPO. Addition of maleic anhydride increased the encapsulating ratio and the stable encapsulating ratio of encapsulated nano‐CaCO3. For the encapsulated nano‐CaCO3 prepared in methanol–water, the diameter of the encapsulated nano‐CaCO3 particle increased from 60–70 nm to about 100 nm and the morphology changed from a cube with a sharp edge to spherical with a rough surface. Copyright © 2006 Society of Chemical Industry  相似文献   

2.
The Archimedes' principle and physical theory are attempted to analysis the densification and structure of the polystyrene (PS) composites by melt compounding with CaCO3 having different particle size. The difference between the measured specific volume (ν) andthe theoretically calculated specific volume (νmix), Δν = ν−νmix, can reflect the densification of the composites. It is clearly demonstrated that the PS composites become more condensed with the reduction of the CaCO3 particle size. Especially, when the content for nano‐CaCO3 achieves 2 wt%, the Δν value of the composites reaches the least, which shows the best densification. Meanwhile, the glass transition temperature (Tg) reaches the maximum value of about 100°C by differential scanning calorimetry (DSC) and thermal mechanical analysis (TMA), which indirectly reveals the composites microstructure more condensed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that 2 wt% nano‐CaCO3 uniformly disperses in PS composites. The CaCO3 selected in this experiment has certain toughening effect on PS. The impact and tensile strength increase with addition of nano‐CaCO3, but the elongation at break decreases. When nano‐CaCO3 content achieved 2 wt%, the impact and tensile strength present the maximum value of 1.63 KJ/m2 and 44.5 MPa, which is higher than the pure PS and the composites filled with the same content of micro‐CaCO3. POLYM. COMPOS., 31:1258–1264, 2010. © 2009 Society of Plastics Engineers  相似文献   

3.
To investigate the effect of interfacial interaction on the crystallization and mechanical properties of polypropylene (PP)/nano‐CaCO3 composites, three kinds of compatibilizers [PP grafted with maleic anhydride (PP‐g‐MA), ethylene–octene copolymer grafted with MA (POE‐g‐MA), and ethylene–vinyl acetate copolymer grafted with MA (EVA‐g‐MA)] with the same polar groups (MA) but different backbones were used as compatibilizers to obtain various interfacial interactions among nano‐CaCO3, compatibilizer, and PP. The results indicated that compatibilizers encapsulated nano‐CaCO3 particles, forming a core–shell structure, and two interfaces were obtained in the compatibilized composites: interface between PP and compatibilizer and interface between compatibilizer and nano‐CaCO3 particles. The crystallization and mechanical properties of PP/nano‐CaCO3 composites were dependent on the interfacial interactions of these two interfaces, especially the interfacial interaction between PP and compatibilizer. The good compatibility between PP chain in PP‐g‐MA and PP matrix improved the dispersion of nano‐CaCO3 particles, favored the nucleation effect of nano‐CaCO3, increased the tensile strength and modulus, but reduced the ductility and impact strength of composites. The partial compatibility between POE in POE‐g‐MA and PP matrix had little effect on crystallization and mechanical properties of PP/nano‐CaCO3 composites. The poor compatibility between EVA in EVA‐g‐MA and PP matrix retarded the nucleation effect of nano‐CaCO3, and reduced the tensile strength, modulus, and impact strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

4.
Nano‐CaCO3/polypropylene (PP) masterbatch containing above 80 wt % nano‐CaCO3 was prepared by nano‐CaCO3 coated PP modified by reactive monomers. The chemical interaction, crystallization and melting behavior, thermal stability, morphology, and surface contact angle of masterbatch were investigated with IR, DSC, TEM, TGA, ESCA, and surface contact angle. The results indicated that nano‐CaCO3 was coated by PP graft copolymers in the masterbatch modified by reactive monomers. The graft ratio and crystallization and melting behavior of PP in the masterbatch depended on the type and content of reactive monomer. The crystallization temperatures of masterbatch modified by reactive monomer is methyl methacrylate > butyl acrylate > methyl acrylate ≈ mixture of acrylic acid and styrene > unmodified ≈ maleic anhydride ≈ acrylic acid > styrene. Modification by reactive monomer increased the thermal stability and surface contact angle of masterbatch. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3907–3914, 2006  相似文献   

5.
A procedure to improve the properties of styrene‐butadiene‐styrene (SBS) copolymer modified bitumen by grafting of maleic anhydride (MAH) onto SBS in the presence of benzoyl peroxide (BPO) as initiator was proposed. The effects of the grafting degree (GD) on the properties of modified bitumen were investigated. FTIR spectroscopy was employed to verify the grafting of MAH onto SBS. The GD of MAH onto SBS was determined by a back titration procedure. To assess the effects of the GD of grafted SBS on properties of modified bitumen, the softening point, penetration, ductility, elastic recovery, penetration index, viscosity, storage stability, and dynamic shear properties were tested. Experimental results indicated that the SBS grafted with maleic anhydride (SBS‐g‐MAH) copolymer was successfully synthesized by solvothermal method, and different GD of the SBS‐g‐MAH was obtained by control the MAH concentration. The GD of the MAH onto SBS has great effect on the rheological properties of the modified bitumen, and the high temperature performance and storage stability of modified bitumen were improved with the GD of the MAH onto SBS increasing. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers  相似文献   

6.
采用马来酸酐(MAH)和苯乙烯(St)作为接枝单体,通过溶液聚合法合成接枝极性基团的苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS),然后与聚苯乙烯(PS)基体、碳酸钙(CaCO_3)粒子复合,用傅立叶红外光谱仪表征接枝处理前后SBS表面化学结构的变化;并研究了SBS改性对复合材料微观结构和力学性能的影响.结果表明:双单体溶液聚合法成功地将极性基团接枝在SBS链上;填充SBS-g-MAH后,促进CaCO_3在PS基体中的分散、改善PS-CaCO_3粒子间界面粘接,起到良好的增容作用;SBS-g-MAH和CaCO_3粒子对PS基体具有协同增强增韧作用,同时能提高复合材料的拉伸强度和冲击强度.  相似文献   

7.
The grafting copolymerization of maleic anhydride (MAH) onto styrene‐butadiene‐styrene terpolymer (SBS) was carried out through a new synthesis method––solvothermal synthesis. Infrared (IR) spectra and solid state 13C‐NMR confirmed that maleic anhydride was successfully grafted onto the SBS backbone. The effects of different solvents, different initiators and their concentration, the amount of MAH, SBS concentration, and reaction time on the graft degree were evaluated, and the optimal conditions were obtained. Results indicated that the grafting reaction of MAH onto SBS through solvothermal method can be carried out in both good solvents and poor solvents, which are much different from the traditional solution grafting method, and high grafting degree can be obtained in good solvents. Finally, we also compared the grafting degree (GD) prepared by the solvothermal method with that by the melt grafting method and solution grafting method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5274–5279, 2006  相似文献   

8.
In this paper, a new method was applied to form crosslinking networks in the ethylene–propylene–diene terpolymer (EPDM) matrix with calcium carbonate(CaCO3) particles, which were chemically treated by maleic anhydride (MAH). The tensile test showed that the tensile strength and the elongation at break of the composites were improved significantly, and when the content of CaCO3 was about 20 wt % in the composites, the maximum tensile properties were achieved. The results of swell and solution text showed that the composites had evident crosslinking structure. The results of attenuated transmission reflectance‐Fourier transform infrared (ATR‐FTIR) spectrum proved that the Acid‐Base reaction between CaCO3 and MAH had happened. SEM micrographs showed that the interfacial adhesion between CaCO3 and copolymer was well. The thermogravimetric analysis curves showed that the composites had a new change in mass between 655 and 700°C, which might be the decomposition temperature of calcium maleicate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1810–1815, 2006  相似文献   

9.
T ernary composite of nano‐CaCO3/ethylene‐propylene‐diene terpolymer (EPDM)/polypropylene (PP) with high content of nano‐CaCO3 was prepared by two step compounding route, in which EPDM and nano‐CaCO3 were mixed first, and then melt compounding with PP matrix. The influence of mixing time during the second compounding on distribution of nano‐CaCO3 particles and the impact strength of the ternary composite have been investigated. It was found that the Izod impact strength of composite decreased with increasing mixing time. The observation of transmission electron microscopy obviously showed that nano‐CaCO3 particles transported from EPDM to PP matrix firstly and then from PP to the vicinity of EPDM dispersed phase with the increase of mixing time. This phenomenon can be well explained by the minimization of the dissipative energy and the Young's equation. The scanning electron microscope images show that lots of nano fibrils exist at the interface between nano‐CaCO3 agglomerates and matrix, which can dissipate lots of energy. The toughening mechanism has been interpreted in terms of three‐stage‐mechanism: stress concentration, void and shear band formation, and induced shear yielding. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

10.
Nano‐CaCO3/homo‐PP composites were prepared by melt‐blending using twin‐screw extruder. The results show that not only the impact property but also the bending modulus of the system have been evidently increased by adding nano‐CaCO3. The nano‐CaCO3 particles have been dispersed in the matrix in the nanometer scale which was investigated by means of transmission electron microscopy (TEM). The toughening mechanism of nano‐CaCO3, investigated by means of dynamical mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM), lies on that the nano‐CaCO3 particles take an action of initiating and terminating crazing (silver streak), which can absorb more impact energy than the neat PP. At the same time, the nano‐CaCO3 particles, as the nuclear, decrease the crystal size of PP, the results of which were investigated by means of polarized optical microscope (POM). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

11.
β‐Polypropylene composites containing calcium carbonate treated by titanate coupling agent (T‐CaCO3) and maleic anhydride grafted PP (PP‐g‐MAH) were prepared by melt compounding. The crystallization, morphology and mechanical properties of the composites were investigated by means of differential scanning calorimetry, wide‐angle X‐ray diffraction, polarized light microscopy, scanning electron microscopy and mechanical tests. It is found that both T‐CaCO3 and NT‐C are able to induce the formation of β‐phase, and NT‐C greatly increases the β content and decreases the spherulitic size of PP. PP‐g‐MAH facilitates the formation of β‐form PP and improves the compatibility between T‐CaCO3 and PP. Izod notched impact strength of β‐PP/T‐CaCO3 composite is higher than that of PP/T‐CaCO3 composite, indicating the synergistic toughening effect of T‐CaCO3 and β‐PP. Incorporation of PP‐g‐MAH into β‐PP/T‐CaCO3 composite further increases the content of β‐crystal PP and improves the impact strength and tensile strength when T‐CaCO3 concentration is below 5 wt%. The nonisothermal crystallization kinetics of β‐PP composites is well described by Jeziorny's and Mo's methods. It is found that NT‐C and T‐CaCO3 accelerate the crystallization rate of PP but the influence of PP‐g‐MAH on crystallization rate of β‐PP composite is marginal. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers  相似文献   

12.
As novel piezoelectric materials, carbon‐reinforced polymer composites exhibit excellent piezoelectric properties and flexibility. In this study, we used a styrene–butadiene–styrene triblock copolymer covalently grafted with graphene (SBS‐g‐RGO) to prepare SBS‐g‐RGO/styrene–butadiene–styrene (SBS) composites to enhance the organic solubility of graphene sheets and its dispersion in composites. Once exfoliated from natural graphite, graphene oxide was chemically modified with 1,6‐hexanediamine to functionalize with amino groups (GO–NH2), and this was followed by reduction with hydrazine [amine‐functionalized graphene oxide (RGO–NH2)]. SBS‐g‐RGO was finally obtained by the reaction of RGO–NH2 and maleic anhydride grafted SBS. After that, X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and other methods were applied to characterize SBS‐g‐RGO. The results indicate that the SBS molecules were grafted onto the graphene sheets by covalent bonds, and SBS‐g‐RGO was dispersed well. In addition, the mechanical and electrical conductivity properties of the SBS‐g‐RGO/SBS composites showed significant improvements because of the excellent interfacial interactions and homogeneous dispersion of SBS‐g‐RGO in SBS. Moreover, the composites exhibited remarkable piezo resistivity under vertical compression and great repeatability after 10 compression cycles; thus, the composites have the potential to be applied in sensor production. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46568.  相似文献   

13.
Nano‐CaCO3/polypropylene (PP) composites modified with polypropylene grafted with acrylic acid (PP‐g‐AA) or acrylic acid with and without dicumyl peroxide (DCP) were prepared by a twin‐screw extruder. The crystallization and melting behavior of PP in the composites were investigated by DSC. The experimental results showed that the crystallization temperature of PP in the composites increased with increasing nano‐CaCO3 content. Addition of PP‐g‐AA further increased the crystallization temperatures of PP in the composites. It is suggested that PP‐g‐AA could improve the nucleation effect of nano‐CaCO3. However, the improvement in the nucleation effect of nano‐CaCO3 would be saturated when the PP‐g‐AA content of 5 phf (parts per hundred based on weight of filler) was used. The increase in the crystallization temperature of PP was observed by adding AA into the composites and the crystallization temperature of the composites increased with increasing AA content. It is suggested that the AA reacted with nano‐CaCO3 and the formation of Ca(AA)2 promoted the nucleation of PP. In the presence of DCP, the increment of the AA content had no significant influence on the crystallization temperature of PP in the composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2443–2453, 2004  相似文献   

14.
Acrylonitrile‐butadiene‐styrene (ABS)/poly(methyl meth‐acrylate) (PMMA)/nano‐calcium carbonate (nano‐CaCO3) composites were prepared in a corotating twin screw extruder. Four kinds of nano‐CaCO3 particles with different diameters and surface treatment were used in this study. The properties of the composites were analyzed by tensile tests, Izod impact tests, melt flow index (MFI) tests, and field emission scanning electron microscopy (FESEM). This article is focused on the effect of nano‐CaCO3 particles' size and surface treatment on various properties of ABS/PMMA/nano‐CaCO3 composites. The results show that the MFI of all the composites reaches a maximum value when the content of nano‐CaCO3 is 4 wt%. In comparison with untreated nano‐CaCO3 composites, the MFI of stearic acid treated nano‐CaCO3 composites is higher and more sensitive to temperature. The tensile yield strength decreases slightly with the increase of nano‐CaCO3 content. However, the size and surface treatment of nano‐CaCO3 particles have little influence on the tensile yield strength of composites. In contrast, all of nano‐CaCO3 particles decrease Izod impact strength significantly. Stearic acid treated nano‐CaCO3 composites have superior Izod impact strength to untreated nano‐CaCO3 composites with the same nano‐CaCO3 content. Furthermore, the Izod impact strength of 100 nm nano‐CaCO3 composites is higher than that of 25 nm nano‐CaCO3 composites. POLYM. COMPOS., 31:1593–1602, 2010. © 2009 Society of Plastics Engineers  相似文献   

15.
PVC/Blendex/Nano‐CaCO3 composites were prepared by melt‐blending method. The Blendex (BLENDEX® 338) (GE Specialty Chemicals Co., Ltd., Shanghai, China) was an acrylonitrile‐butadiene‐styrene copolymer with high butadiene content. The fracture behavior of PVC/Blendex/nano‐CaCO3 composites was studied using a modified essential work of fracture model, U/A = u0 + udl, where u0 is the limiting specific fracture energy and ud is the dissipative energy density. The u0 of PVC/Blendex blend could be greatly increased by the addition of nano‐CaCO3, while the ud was decreased. Nano‐CaCO3 with particle size of 38 nm increased the u0 of PVC/Blendex blend more effectively than that with particle size of 64 nm, when nano‐CaCO3 content was below 10 phr. Both the u0 and ud of PVC/Blendex/nano‐CaCO3 composites were not much affected by increasing specimen thickness from 3 mm to 5 mm, while the two fracture parameters were increased with increasing loading rate from 2 mm/min to 10 mm/min, and ud was found to be more sensitive to the loading rate than u0. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 953–961, 2005  相似文献   

16.
The isothermal crystallization and subsequent melting behavior of poly(trimethylene terephthalate) (PTT) composites filled with nano‐CaCO3 were investigated at designated temperatures with differential scanning calorimetry. The Avrami equation was used to fit the isothermal crystallization. The Avrami exponents were determined to be 2–3 for the neat PTT and PTT/CaCO3 composites. The particles of nano‐CaCO3, acting as nucleating agents in the composites, accelerated the crystallization rate, with the half‐time of crystallization decreasing or the growth rate constant (involving both nucleation and growth rate parameters) increasing. The crystallization activation energy calculated from the Arrhenius formula was reduced as the nano‐CaCO3 content increased from 0 to 2%, and this suggested that nano‐CaCO3 made the molecular chains of PTT easier to crystallize during the isothermal crystallization process. Subsequent melting scans of the isothermally crystallized composites exhibited triple or double melting endotherms: the greater the content was of nano‐CaCO3, the lower the temperature was of the melting peak. The degree of crystallization deduced from the melt enthalpy of composites with the proper concentration of nano‐CaCO3 was higher than that of pure PTT, but it was lower when the nano‐CaCO3 concentration was more than 2%. The transmission electron microscopy pictures suggested that the dispersion state of nano‐CaCO3 particles in the polymer matrix was even when its concentration was no more than 2%, whereas some agglomeration occurred when its concentration was 4%. Polarized microscopy pictures showed that much smaller or less perfect crystals formed in the composites because of the interaction between the molecular chains and nano‐CaCO3 particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007  相似文献   

17.
A new grafting method was developed to incorporate maleic anhydride directly onto solid‐state polypropylene powders. Maleic anhydride grafts altered the nonpolar characteristics of polypropylene so that much better mixing was achieved in blends and composites of polypropylene with many other polymers and fillers. Maleic anhydride was grafted onto polypropylene by the peroxide‐catalyzed swell grafting method, with a maximum extent of grafting of 4.60%. Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, tensile testing, and impact testing were used to characterize the isotactic polypropylene (iPP), maleic anhydride grafted polypropylene (MAH‐giPP), and (isotactic polypropylene)/(calcium carbonate) composites (iPP/CaCO3). The crystallinity and heat of fusion of the MAH‐giPP decreased as the extent of grafting increased. The mechanical properties of the CaCO3 filled polypropylene were improved by adding MAH‐giPP as a compatibilizing agent. The dispersion of the fillers in the polymer matrix and the adhesion between the CaCO3 particles and the polymer matrix were improved by adding the compatibilizer.  相似文献   

18.
Styrene–butadiene–styrene (SBS) was grafted with dibutyl maleate (DBM), methacrylic acid (MAA), or maleic anhydride (MAH) by 60Co γ‐rays. The grafted SBS was blended with polyamide 6 (PA6). The compatibility of the PA6/SBS blends was studied with scanning electron microscopy and rheological measurements. The results showed significant improvement in the compatibility of PA6 blended with MAH‐ or MAA‐grafted SBS, with the former being more effective, whereas grafting DBM was ineffective in this respect. Mechanisms of the compatibility enhancement and ineffectiveness are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

19.
CaCO3/acrylonitrile‐butadiene‐styrene (ABS) and CaCO3/ethylene‐vinyl acetate copolymer (EVA)/ABS nanocomposites were prepared by melting‐blend with a single‐screw extruder. Mechanical properties of the nanocomposites and the dispersion state of CaCO3 particles in ABS matrix were investigated. The results showed that in CaCO3/EVA/ABS nanocomposites, CaCO3 nanoparticles could increase flexural modulus of the composites and maintain or increase their impact strength for a certain nano‐CaCO3 loading range. The tensile strength of the nanocomposites, however, was appreciably decreased by adding CaCO3 nanoparticles. The microstructure of neat ABS, CaCO3/ABS nanocomposites, and CaCO3/EVA/ABS nanocomposites was observed by scanning electron microscopy. It can be found that CaCO3 nanoparticles were well‐dispersed in ABS matrix at nanoscale. The morphology of the fracture surfaces of the nanocomposites revealed that when CaCO3/EVA/ABS nanocomposites were exposed to external force, nano‐CaCO3 particles initiated and terminated crazing (silver streak), which can absorb more impact energy than neat ABS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

20.
Nano‐calcium carbonate (nano‐CaCO3) was used in this article to fill acrylonitrile–butadiene–styrene (ABS)/poly(methyl methacrylate) (PMMA), which is often used in rapid heat cycle molding process (RHCM). To achieve better adhesion between nano‐CaCO3 and ABS/PMMA, nano‐CaCO3 particles were modified by using titanate coupling agent, aluminum–titanium compound coupling agent, and stearic acid. Dry and solution methods were both utilized in the surface modification process. ABS/PMMA/nano‐CaCO3 composites were prepared in a corotating twin screw extruder. Influence of surface modifiers and surface modification methods on mechanical and flow properties of composites was analyzed. The results showed that collaborative use of aluminum–titanium compound coupling agent and stearic acid for nano‐CaCO3 surface modification is optimal in ABS/PMMA/nano‐CaCO3 composites. Coupling agent can increase the melt flow index (MFI) and tensile yield strength of ABS/PMMA/nano‐CaCO3 composites. The Izod impact strength of composites increases with the addition of titanate coupling agent up to 1 wt %, thereafter the Izod impact strength shows a decrease. The interfacial adhesion between nano‐CaCO3 and ABS/PMMA is stronger by using solution method. But the dispersion uniformity of nano‐CaCO3 modified by solution method is worse. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

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