This paper deals with in situ compatibilization of PE/PS blends via Friedel-Crafts reaction, performed at the interphase. Two polyethylenes having different molecular weights, and the same PS, were used along a wide range of catalyst concentration. The influence of the graft copolymer architecture and content on the efficiency of blend compatibilization was studied. The emulsifying effect, morphological aspects and mechanical behavior were also assessed for these blends. The amount of copolymer formed increases with catalyst concentration and the short chain length fraction of the homopolymers. The high molecular weight (MW) copolymers behaved as better compatibilizers as they showed, at the cmc, greater graft copolymer concentration than the low MW ones. A substantial increase in interfacial adhesion and particle size reduction was observed, even at catalyst concentrations as low as 0.3 wt%. In correspondence, mechanical properties, like ductility and yield strength, were enhanced by the effect of this Friedel-Crafts reaction's compatibilization. 相似文献
Objectives: OpenMusic (OM) is a domain-specific visual programming language designed for computer-aided music composition. This language based on Common Lisp allows composers to develop functional processes generating or transforming musical data, and to execute them locally by demand-driven evaluations. As most historical computer-aided composition environments, OM relies on a transformational declarative paradigm, which is hard to conciliate with reactive data-flow (an evaluation scheme more adequate to the development of interactive systems). We propose to link these two evaluation paradigms in the same and consistent visual programming framework.Methods: We establish a denotational semantics of the visual language, which gives account for its demand-driven evaluation mechanism and the incremental construction of programs. We then extend this semantics to enable reactive computations in the functional graphs.Results: The resulting language merges data-driven executions with the existing demand-driven mechanism. A conservative implementation is proposed.Conclusions: We show that the incremental construction of programs and their data-driven and demand-driven evaluations can be smoothly integrated in the visual programming workflow. This integration allows for the propagation of changes in the programs, and the evaluation of graphically designed functional expressions as a response to external events, a first step in bridging the gap between computer-assisted composition environments and real-time musical systems. 相似文献
This paper describes a new reactive blending approach to improve the compatibility of poly(l-lactide) (PLLA) and poly(?-caprolacton) (PCL). For this purpose, the ring-opening polymerization of l-lactide (LLA) was carried out in the presence of PCL-OH (OH groups on one end). The P(CL-b-LLA) block copolymers were in situ formed during polymerization, and as a result, PLLA/P(CL-b-LLA) blends were obtained. The characterization of GPC and 1H NMR verified the synthesis of PLLA/P(CL-b-LLA) blends. Furthermore, the 13C NMR spectroscopy showed that no transesterification reaction occurred to a significant extent during LLA polymerization process. The in situ formed P(CL-b-LLA) compatibilizes the phase separated structure of PCL domains in PLLA matrix. The size of PCL domains in PLLA matrix became much smaller than that in a solution blended sample. The average sizes of PCL domains are controllable in the level of sub-micron scale. 相似文献
The air–solid photocatalytic degradation of organic dye films Acid Blue 9 (AB9) and Reactive Black 5 (RBk5) is studied on Pilkington Activ™ glass. The Activ™ glass comprises of a colorless TiO2 layer deposited on clear glass. The Activ™ glass is characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). Using AFM, the TiO2 average agglomerate particle size is 95 nm, with an apparent TiO2 thickness of 12 nm. The XRD results indicate the anatase phase of TiO2, with a calculated crystallite size of 18 nm.
Dyes AB9 and RBk5 are deposited in a liquid film and dried on the Activ™ glass to test for photodecolorization in air, using eight UVA blacklight-blue fluorescent lamps with an average UVA irradiance of 1.4 mW/cm2. A novel horizontal coat method is used for dye deposition, minimizing the amount of solution used while forming a fairly uniform dye layer. About 35–75 monolayers of dye are placed on the Activ™ glass, with a covered area of 7–10 cm2. Dye degradation is observed visually and via UV–vis spectroscopy.
The kinetics of photodecolorization satisfactorily fit a two-step series reaction model, indicating that the dye degrades to a single colored intermediate compound before reaching its final colorless product(s). Each reaction step follows a simple irreversible first-order reaction rate form. The average k1 is 0.017 and 0.021 min−1 for AB9 and RBk5, respectively, and the corresponding average k2 is 2.0 × 10−3 and 1.5 × 10−3 min−1. Variable light intensity experiments reveal a p = 0.44 ± 0.02 exponent dependency of initial decolorization rate on the UV irradiance. Solar experiments are conducted outdoors with an average temperature, water vapor density, and UVA irradiance of 30.8 °C, 6.4 g water/m3 dry air, and 1.5 mW/cm2, respectively. For AB9, the average solar k1 is 0.041 min−1 and k2 is 5.7 × 10−3 min−1. 相似文献
Various aspects of alkyd emulsion technology have been investigated. The influence of alkyd oil length, acid value and hydroxyl number and type of surfactant used as emulsifier, on shear stability of alkyds emulsions have been studied. It was found that the acid value was the most important alkyd parameter, the stability increasing with increasing oil length. It is also shown that anionic surfactants give emulsions with small droplet sizes at lower concentrations than do nonionics. Polymerizable nonionic surfactants have been tested as emulsifiers and compared with conventional surfactants of the same hydrophilic lipophilic balance (HLB). It was found that surfactants capable of participating in the autoridative curing process give faster drying and improved film hardness compared with nonreactive surfactants. The distribution of driers between the alkyd phase and the water phase has been investigated. It was found that low pH and the use of hydrophilic anionic surfactants, such as sodium dodecyl sulphate, favour partitioning of cobalt into the aqueous phase which is unfavourable with respect to drying properties. 相似文献