Polymer blend

About: Polymer blend is a research topic. Over the lifetime, 18474 publications have been published within this topic receiving 437183 citations. The topic is also known as: polymer mixture & Polymerblend 或者 Polyblend.

Modified epoxy resins, processes for making and using same and substrates coated therewith

Abstract: Discloses a technique for modifying an epoxy resin by reacting with addition copolymerizable monomer in the presence of at least 3% of benzoyl peroxide at about 110° C. to 120° C., or the free radical initiating equivalent thereof. The reaction mixture obtained contains: (a) unreacted epoxy resin; (b) graft polymer; and (c) associatively formed but ungrafted addition polymer. The graft polymer is formed from the epoxy resin by the grafting of addition polymer onto aliphatic backbone carbons of the epoxy resin, such grafting being at carbons that have either one or two hydrogens bonded thereto in the ungrafted state. The process is useful for making polymer blends for coating compositions, and particularly, coatings for cans for foods and beverages, especially for beer. The coating compositions may be aqueous dispersions ready for spray application, or concentrate that can be made up readily into aqueous sprayable coating compositions. Solvent vehicles may also be used.

Interpretation of a New Interface-Governed Relaxation Process in Compatibilized Polymer Blends

Abstract: We have analyzed the influence of different amounts ω be of two diblock copolymers, poly(styrene-b-methyl methacrylate) (sm blend series) and poly(cyclohexyl methacrylate-b-methyl methacrylate) (cm blend series), on the morphological and rheological characteristics of a blend containing w = 7.5 wt % polystyrene in poly(methyl methacrylate) matrix. The morphological analysis is based on the sphere size distribution function, which was determined from the image analysis of the transmission electron micrographs. Using this function and assuming that all block copolymers are located at the interface, the interfacial area per copolymer joint, Σ, was calculated. From its hyperbolic dependence on ω bc the value at the critical micelle concentration, Σ cmc , was found to be about 10 nm 2 for both systems. The rheological analysis reveals that in addition to the form relaxation process, well-known for polymer blends, a new relaxation process is observed for these systems. Its relaxation time, τ β , has been studied in dependence on the amount of added block copolymers. The observed phenomena for each blend series, i.e. constant blend viscosity, slight shift of the form relaxation times τ 1 , and systematic shift of the interface governed relaxation time τ β (τ β > τ 1 ), have been interpreted quantitatively. In contrast to τ 1 , τ β is less influenced by the interfacial tension but is mainly governed by an additional contribution, the interfacial shear modulus. Formulas were derived from an expanded version of the Palierne emulsion model which allows the determination of the proposed interfacial properties from rheological measurements. In general, the interfacial tension decreases with increasing amount of block copolymer, and the decrease is more pronounced for the cm blend series. The interfacial shear modulus increases during compatibilization from 0 to amounts which are in the range of 20-30% of the interfacial tension. The decrease of interfacial tension is in good agreement with predictions from Leibler's brush model extended by Dai et al. In conclusion, it was found that the Palierne model with an nonisotropical interfacial stress state is quantitatively correct to describe the observed phenomena for those blends.

Mechanical Properties of Polypropylene Blended with Esterified and Alkylated Lignin

Abstract: Lignin does not show miscibility with com- mercial polyolefins. Therefore, industrial waste lignin was modified in two different ways and subsequently blended with commercial polypropylene (PP) up to 25 wt %. A Brabender electronic plasticorder was used for melt mix- ing at 190 � C. The influence of different modifications on the mechanical properties and processing stability was studied for both polymer blends. The blends of PP and lig- nin modified (esterified) with maleic anhydride showed less deterioration in the mechanical properties compared to blends of PP and alkylated lignin with dichloroethane. Intermolecular interactions between the PP matrix and modified lignin were concluded on the basis of indicative values derived from various relevant theoretical models to