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In this paper, a series of novel trans-1, 4-polyisoprene/isotactic polybutene (TPI/iPB) in-reactor blends were synthesized by isoprene and butene sequential two-stage polymerization technology with spherical Ti[Cl.sub.4]/Mg[Cl.sub.2] type Ziegler-Natta catalyst. The components, structures, and properties of the asobtained TPI/iPB reactor blends were characterized by gel permeation chromatography, Fourier transform Infrared spectroscopy, and differential scanning calorimetry. The active trans-1, 4-polyisoprene (TPI) particles obtained in the initial isoprene polymerization by the Z-N catalyst can be acted as microreactors to initiate butene polymerization subsequently. The TPI/iPB reactor blends with varied components were in situ synthesized within the reactor. The preparative-temperature rising elution fractionation (p-TREF) technique was used to fractionate the TPI/iPB reactor blends based on the elution temperature ranged from -40[degrees]C to 90[degrees]C. The weight distribution and microstructure of each fraction were investigated. The reactor blends are composed of crystallizable high trans-1, 4-uint polyisoprene obtained from the first-stage isoprene polymerization, high isotactic polybutene obtained from the secondstage butene polymerization and TPI-b-iPB block copolymer with different sequence structure obtained from the initial time of the second stage. This work is expected to propose the possible polymerizations of a-olefins and conjugated dienes by using heterogeneous Ziegler-Natta catalyst and provide a kind of novel rubber/plastic reactor blend materials. Highlights * The first synthesis of the trans-1,4-polyisoprene/isotactic polybutene reactor blends. * p-TREF technique was used to analyze the composition of TPI/iPB reactor blends. * Detailed structure characterization of the fractions including GPC and NMR * TPI-b-iPB block copolymer can be obtained through the sequential polymerization. * Rubber/plastic reactor blend materials were fabricated by the Z-N catalyst. KEYWORDS 4-polyisoprene, in-reactor blends, polybutene, temperature rising elution fractionation, trans-1, Ziegler-Natta catalyst, 1 | INTRODUCTION The discovery of Ziegler-Natta catalysts has been one of the greatest developments in the synthesis of stereospecific polymers in both academy and modern industry. (1-4) The first [...]

The objective of the present study was the preparation and characterization of poly(butylene adipate-co-terephthalate) (PBAT) and thermoplastic starch (TPS) blends reinforced with cellulose nanoparticles (CNCs) by extrusion. The work was conducted in four steps. Initially, the CNCs were prepared from eucalyptus cellulose pulp by acid hydrolysis. The second step was the preparation of the nanocomposite (TPS-CNC), composed of cassava starch, CNC, glycerol, and citric and stearic acids, by double screw extrusion. The third step was the preparation of PBAT/TPS-CNC blends in twin-screw extruders. In the fourth step, the films were produced by flat extrusion. Blends exhibited similar rheological behavior, increasing the CNC concentration in blends increased the viscosity as a function of the shear rate, and altered the behavior of the shear storage (G') and shear loss (G') curves as a function of the oscillation frequency ([omega]). The presence of CNC in blend provided improvements significant in mechanical properties, with 120% increase in Young's modulus, and 46% increase in maximum tensile. Thermal behavior (thermogravimetric analysis and differential scanning calorimetry) was altered with the incorporation of the CNC, showing a single melt peak ([T.sub.m]) and a slight increase in [T.sub.g], indicating good dispersion between the phases of the blends, corroborating with the fracture surface microscopy of films. KEYWORDS blends, cellulose nanoparticle, poly(butylene adipate-co-terephthalate), thermoplastic starch, rheological properties, 1 | INTRODUCTION Synthetic polymers derived from fossil sources, despite being of great use, mainly for the plastic packaging industry, are increasingly associated with environmental problems. [1,2,3] The indiscriminate disposal [...]

Controlled-rheology poly(l-butene) resins have been produced by chemical modification of commodity poly(l-butene) (PB-I) resins through reactive processing with an organic peroxide. Using various amounts of peroxide, samples have been produced and have been analyzed in terms of their molecular and rheological properties. Molecular weight distributions (MWD) as determined by gel permeation chromatography (GPC) indicate that polydispersity (PDI) remains approximately constant but weight-average molecular weight (Mw) decreases with increasing peroxide concentration. These trends are in agreement with predictions from a kinetic model previously developed for the production of controlled-rheology polypropylene. Linear viscoelastic measurements indicate that the modified samples are thermorheologically simple and that zero-shear viscosity decreases with increasing peroxide concentration while flow activation energy remains approximately constant. Finally, no significant variation in melting and crystallization properties was observed for the range of peroxide concentrations used. Based on these results, it is proposed that tailor-made controlled-rheology poly(l-butene) resins can be produced easily through reactive extrusion operations similar to those used for the production of controlled-rheology polypropylene (CRPP). KEYWORDS reactive processing, modification, polyolefins, rheology, 1 | INTRODUCTION Poly(l-butene) (PB-I) is a linear, highly isotactic, semicrystalline polymer which is produced during polymerization of 1-butene with a stereospecific catalyst. Commercially, polymerization of 1-butene can be carried [...]

The potential of exchange reactions using titanium butoxide (TBT) as catalyst for the compatibilization of poly(butylene succinate) and poly(propylene carbonate) was explored, and the effects of high speed reactive extrusion on the ester-carbonate exchange reaction were studied. The feasibility of this functionalization route was contrasted to the free radical grafting (FRG) type using maleic anhydride and a peroxide. First, batch mixing and solution blending were conducted to determine the suitable amount of catalyst for blends of this kind. Then, blends at different screw speeds, reaching 1,000 rpm were compounded with catalyst on a twin-screw extruder. Spectroscopy techniques corroborated the formation of block and graft copolymers on the TBT and FRG samples, respectively. Both compatibilization paths produce a positive change in the mechanical properties of the system that was accompanied by a finer droplet size and better interfacial interaction. Specifically, the high-speed runs using a catalyst demonstrated a 177% improvement of the strain at break, proving that the high mechanical energy imparted impacts positively the mixing performance., INTRODUCTION The compatibilization of immiscible polymer blends is in essence an emulsification process that targets a fine phase morphology resistant to coalescence and an enhancement of the mechanical properties. Compatibility [...]

The compounds 1,4-butanedioi, succinic anhydride, and nanocellulose (NCC) were used to synthesize poly(butylene succinatej-grafted Nanocrystalline Cellulose (PBS-g-NCC) nanocomposites via polymerization in situ. The resulting structures were examined by transmission electron microscopic (TEM), scanning electron microscope (SEM), [sup.1]H and [sup.13]C-nuclear magnetic resonance spectroscopic (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) analyses. TEM showed the cellulose to be nanoscale and SEM analysis indicated that 3 wt% NCC dispersed well in PBS matrix. [sup.1]H and [sup.13]C-NMR analyses indicated the product to possess peaks characteristic of PBS. DSC analysis clearly showed that the NCC increased the PBS crystallinity when 3 wt% NCC was introduced into PBS matrixes by polymerization in situ, compared to pure PBS. TGA illustrated that the thermal stability of PBS-g-NCC was better than that of pure PBS, when 3 wt% NCC was added. XRD analysis suggested that 3 wt% NCC improved PBS crystallinity, which was in good agreement with the present DSC results., INTRODUCTION Sustainable polymers derived from renewable resources have attracted increasing consideration as they are not only petroleum independent but also environmentally friendly [1-3]. The use of sustainable polymers provides a [...]

Melamine resin microcapsules encapsulating liquid paraffin as core materials are synthesized. By using melt blending method, different ratios of microcapsules and modified potassium titanate whiskers (PTWs) are added to poly(butylene terephthalate) (PBT) matrix to fabricate the binary and ternary PBT composites. The effect of oil-loaded microcapsules content on mechanical properties and tribological properties of PBT composites are evaluated by electronic universal testing machine and high speed block-on-ring wear tester, respectively. The results indicate that the incorporation of microcapsule could significantly reduce the friction and wear of the composites mainly due to the self-lubricating effect of liquid paraffin released from the ruptured microcapsule during the friction process; however, the mechanical properties of the PBT binary composites are reduced. Hence, PTWs are adopted to effectively improve the mechanical properties of materials which could improve the tribological properties of the ternary composites as well due to the synergistic effects of microcapsules and PTWs., INTRODUCTION Poly(butylene terephthalate) (PBT) is a kind of semicrystalline polymer possessing excellent mechanical properties, wear resistance, and chemical resistance which is widely used in automotive, electrical, and other fields [1-4]. [...]

Nonisothermal crystallization kinetics of poly(butylene terephthalate) (PBT)/glass fiber (GF) and PBT/epoxidized ethylene propylene diene rubber (eEPDM)/GF composites were investigated by differential scanning calorimetry (DSC) at a cooling rates of 2.5, 5, 10, and 20[degrees]C/min, respectively. Morphologies of samples were observed with scanning electron microscopy and polarized optical microscopy. The specimens were prepared by melt blending. Analyses of the melt crystallization data by various macrokinetic models such as Jeziorny-modified Avrami, Liu-Mo models, and Lauritzen-Hoffman equation revealed that GF accelerated the crystallization rate of PBT; furthermore, the eEPDM had two functions: on the one hand, eEPDM promoted PBT to form nuclei; on the other hand, eEPDM hindered the diffusion of polymer chains, but the nucleation effect exceeded the diffusion effect, thus, the eEPDM could increase the crystallization rate of PBT in PBT/eEPDM/GF. These results were further supported by the effective activation energy calculated by isoconversional method of Friedman., INTRODUCTION Poly(butylene terephthalate) (PBT), a semicrystalline thermoplastic polyester has excellent dimensional stability, high strength, chemical resistance, and fast rate of crystallization, and it is well suited for injection molding because [...]

In this study, three types of fluorinated polyacrylates (PBFB, PBFS, and PMFA) were synthesized by 4-gembis(2,2,3,3,4,4,5,5,5-nonafluoropentyl)-1-butene, 4-gem-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyl)-methine-1-styrene, and 3,3,4,4,5,5,6,6,6-nonafluorohexyl acrylate, respectively, as monomers via emulsion polymerization. Particle size, particle size distribution, and zeta potential were tested to assess the emulsion stability. Afterwards, the latexes were coated onto fabrics to obtain gem-bis(fluoroalkyl)-cotton. The surface properties of the treated cotton fabrics were analyzed by X-ray photoelectron spectroscopy and water contact angle. It was found that, when controlling the fluorine content level to be similar, the water contact angles of gem-bis(fluoroalkyl)-cottons were 127[degrees] [+ or -] 0.5[degrees] and 134.9[degrees] [+ or -] 0.7[degrees], respectively, which were both higher than that of mono-fluoroalkyl-cotton (PMFA-cotton of 125.2[degrees] [+ or -] 0.2[degrees]). This showed that gem-bis-fluoroalkyl groups could provide better hydrophobic performance than the mono-fluoroalkyl group, especially when the rigid benzene was used as a side-chain bridged group.Key words: fluorinated polyacrylate, emulsion polymerization, waterproof property, gem-bis-fluoroalkyl.Dans le cadre de la présente étude, nous avons synthétisé trois types de polyacrylates fluorés (le PBFB, le PBFS et le PMFA) par polymérisation en émulsion, à partir des monomères respectifs, soit le 4-gem-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyl)-1-butène, le 4-gem-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyl)méthine-1-styrène et l'acrylate de 3,3,4,4,5,5,6,6,6-nonafluorohexyle. Nous avons déterminé la taille des particules, la distribution granulométrique et le potentiel zêta afin d'évaluer la stabilité de l'émulsion. Par la suite, nous avons recouvert des tissus de ces latex pour obtenir un coton gem-bis(fluoroalkylé). Nous avons analysé par spectroscopie de photoélectrons X et mesure de l'angle de contact avec l'eau les propriétés de surface de ces tissus de coton traités. Nous avons observé que, lorsque leurs concentrations de fluor étaient maintenues similaires, les deux cotons gem-bis(fluoroalkylés) présentaient un angle de contact avec l'eau (127[degrees] [+ or -] 0,5[degrees] et 134,9[degrees] [+ or -] 0,7[degrees], respectivement) supérieur à celui du coton monofluoroalkylé (PMFA-coton; 125,2[degrees] [+ or -] 0,2[degrees]). Ces résultats indiquent que les groupes gem-bis-fluoroalkyles pourraient conférer au coton de meilleures propriétés hydrophobes que le groupe monofluoroalkyle, en particulier si un noyau benzène rigide est employé comme espaceur de chaîne latérale. [Traduit par la Rédaction]Mots-clés : polyacrylate fluoré, polymérisation en émulsion, imperméabilité, gem-bis-fluoroalkyle., IntroductionFluorinated polyacrylates have been widely used in textile, leather, and paper industries due to a number of their properties such as low surface energy, high thermal stability, excellent film-forming property, [...]