Preparation of asymmetric film by blending two kinds of polymer emulsions having greatly different storage stabilities

Okubo, Masayoshi; He, Yuan

doi:10.1002/app.1991.070420810

Cited by 12 publications

(4 citation statements)

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“…Similar asymmetric distribution of particles across the thickness of a latex blend film has been reported by Okubo et al 28,29 on latex blends prepared from poly(butyl acrylate) (PBA) and poly(ethyl acrylate-methyl methacrylate) (P(EA-MMA)) copolymer, with large PBA particles (tacky) at the glass/polymer interface and small P(EA-MMA) particles (non-tacky) at the air/polymer interfaces. This uneven distribution of two dissimilar particles, attributed to disparity in latex storage stabilities in the blends, was deduced indirectly from tackiness measurement.…”

Section: Morphology Of Nr/pmma Latex Blend Filmssupporting

confidence: 74%

Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes

Khew

Liew

2001

Surface & Interface Analysis

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Colloidally stable latex blends of natural rubber (NR) and poly(methyl methacrylate) (PMMA) latexes containing up to 50 wt.% PMMA can be prepared by mixing commercial NR ammoniated latex concentrate and monodisperse PMMA latex dispersion. The clarity and tackiness of the films obtained depend on the PMMA content; films become opaque and non-tacky at >30 wt.% PMMA content. The morphology of these films shows asymmetric distribution of the PMMA particles across the thickness of the film. There is preferential enrichment of PMMA particles at both the air/polymer and glass/polymer interfaces and a predominating NR interior. More PMMA particles are accumulated preferentially at the glass/polymer interface than at the air/polymer interface. The accumulation of the PMMA particles at the interface is strongly dependent on the size and concentration of the PMMA particles. The formation of these asymmetric latex films is explained in terms of the surface energetics, compatibility, T g and density of the polymers, stability of the component latex, surface chemistry and particle size of the latex particles used. Copyright  2001 John Wiley & Sons, Ltd. KEYWORDS: asymmetric latex film; natural rubber latex; poly(methyl methacrylate) latex; latex blend film morphology; natural and synthetic latex blend INTRODUCTIONSynthetic latexes are used extensively in the paints and coating industry. This application requires the latex particles, on drying, to form a continuous film. However, good filmforming latex lacks mechanical strength in its film. Thus, low-T g latexes have good film-forming abilities but the films possess a low Young's modulus. Various techniques have been used to overcome this problem. For example, filmforming aids frequently have been employed to provide a coherent film.1,2 Another approach is the synthesis of waterborne core/shell latex particles with a high-T g polymer core and a film-forming shell that are able to form a film of elastomeric matrix containing a high-modulus inclusion.3,4 Another technique is by physically blending two polymer latexes with different T g values 2,5 in which the soft particles deform and fill the voids between the hard particles. A blend of a low-T g latex with a high-T g polymer is used in latex-based impact modifiers for polymer resins. In polymer blending, one anticipates obtaining different properties in the blend than those of the individual polymer components. Although polymer blending 7 has been studied for many years, much less attention has been paid to synthetic latex blends. One of the main interests in latex blends is the drive towards zero-volatile organic compounds in the organic coating industry.2 Analysis of morphology and transparency of latex blend films by atomic force microscopy (AFM) and scanning electron microscopy (SEM) has provided insight into the interaction between hard and soft latex particles.8 -10 Although diffusion at the particle/particle interface of miscible polymer components during film formation is studied extensively, 11 -15 little is known ab...

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Section: Morphology Of Nr/pmma Latex Blend Filmssupporting

confidence: 74%

Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes

Khew

Liew

2001

Surface & Interface Analysis

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“…The 36 Cl~ labelled electrolyte was found to be gradually lost during the course of the experiment -presumably due to exchange with the chloride ions of the polymer. (Its presence was not detected in the environment of the experiment.)…”

Section: Steward Et Al Polymer Latex Films Containing Leachable Addimentioning

confidence: 95%

Permeation and Morphology in Polymer Latex Films Containing Leachable Additives

Steward¹,

Hearn

Wilkinson³

et al. 1996

ACS Symposium Series

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This paper reviews recent research, performed at The Nottingham Trent University, into the enhancement of the permeability properties of polymer latex films. Both leachate-free model colloid latices, made by surfactant-free emulsion polymerisation, and commercially available latices, containing surfactants and often requiring plasticiser addition to achieve good film formation, have been studied. Water soluble leachable additives such as sucrose, HPMC and a soluble polymer latex, have been employed to deliberately enhance solute permeant flux, and the transport properties of the films are discussed with reference to film morphology. The use of increasing levels of leachable additive allows the solute transport mechanism to be systematically changed from one in which permeation occurs predominantly by solution-diffusion to a mechanism in which convective diffusion predominates and solute permeation tends to become independent of penetrant solubility in the polymer. The results are discussed in terms of the increased hydration of the polymer resulting from additive leaching.Whenever polymer latex films are used as coatings, then their permeabilities to gases, water vapour and solutes are likely to be of significance. In the case of barrier coatings for substrate protection, a minimisation of the flux would often be desirable, but where coatings are used to aid sustained or controlled release of an active ingredient then an ability to modify the flux is needed. In the latter application, water soluble leachates play an important role.This paper utilises free polymer latex films to investigate the transport properties of such films to a range of permeants, and the effects on film permeability of leachable additives ranging from endogenous surfactants, essential plasticisers and molecular sized

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“…After the 1990s, several researchers published findings on the various preparation methods and the structural features of their products. For example, gradient refractive index materials, one category of the representative PGM, were prepared by a “closed extrusion process.”14 Polymeric sheetlike FGMs were prepared by means of dissolution diffusion, cast, emulsion‐blend, coating, and other ways 15–18. Gradient interpenetrating polymer networks (IPNs) were synthesized where sequential IPNs composed of hydrophilic poly(2‐hydroxyethyl methacrylate) and hydrophobic polystyrene were prepared by photopolymerization 19…”

Section: Introductionmentioning

confidence: 99%

Preparation and structure study of polypropylene/polyamide‐6 gradient materials

Wen

Hou

et al. 2003

J of Applied Polymer Sci

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A polymeric gradient material was prepared by a specific extruding technique in which the weight ratio of two components, polypropylene (PP) and polyamide-6 (PA6), was changed gradually with the progress of process. This columnar gradient material was formed during a combined extruding and winding operating. The gradient variation of specimens sampled along the radius of columnar gradient material was confirmed and characterized through measurements of DSC melting behavior and elemental analysis. The morphological variation was studied using SEM observation. The results indicate that the content of either polymer shows a monotonous variation along the radius direction. With increasing radius, a gradually decreased percentage of PP was observed, whereas PA6 gradually increased. SEM photographs of the specimens sampled at different radii exhibit that the morphology also evolves gradually with variations in the percentage ratio of two polymers. A phase-inversion phenomenon was recognized in this polymeric gradient material and a "dual mode" of dispersed morphology was found in the sandwich zone. These results indicate that the PP/PA6 blend with gradient structure was successfully prepared by use of this unique technique.

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Preparation of asymmetric film by blending two kinds of polymer emulsions having greatly different storage stabilities

Cited by 12 publications

References 1 publication

Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes

Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes

Permeation and Morphology in Polymer Latex Films Containing Leachable Additives

Preparation and structure study of polypropylene/polyamide‐6 gradient materials

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