The influence of particle morphology on the structure and mechanical properties of films cast from hybrid latexes (original) (raw)
Related papers
2005
Three series of hard/soft styrene-acrylic latex based systems with equivalent compositions were prepared either by blending of homopolymer latexes or by preparing structured latex particles having core shell (CS) or inverted core shell (ICS) morphologies. Transmission electron microscopy (TEM) was used to investigate the particle morphologies, which were correlated to the calculated fractional radical penetration for the propagating species during the reactions. The thermo-mechanical properties as well as the morphology of the resulting latex films were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and TEM. The viscoelastic properties of the interphase between the first and second-stage polymers formed in the structured hard/soft latex films, as well as its qualitative amount and also the film morphologies were found to depend on the interplay between thermodynamic and kinetic parameters during the synthesis of the samples. q
Effect of particle morphology on film morphology and properties
2019
The main goal of this PhD thesis was to establish a link between particle morphology and film morphology in hybrid particles latexes. The strategy used to understand it was to study the film morphology and properties of a variety of polymer-polymer hybrid particles latexes. For each system studied, different morphologies with near identical compositions and polymer microstructure were prepared. We demonstrated that film morphology is directly influenced by the particle morphology. Core-shell morphologies led to a honeycomb structure with a MFFT close to the Tg of the soft polymer. Hemispherical morphologies led to the formation of small aggregates of hard polymers in the soft matrix during film formation, which increases the MFFT of the film. Particles containing a hard polymer on the outer part of the particles allowed film formation close to room temperature. Tensile tests were performed for all the systems studied. The honeycomb-like structure displayed by films cast from soft co...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001
Particles with a soft (s) core of poly (n-butyl acrylate)/poly (methyl methacrylate) (PBA/PMMA) copolymer and a hard (h) shell of PMMA were synthesized via a two-stage polymerization process. Two synthesis parameters were investigated: (i) the phase ratio of the core and the shell; and (ii) the compatibility of the two phases. The s/h phase ratio was varied from 100:0 to 0:100. The compatibility between the two phases was changed by (i) using acrylic acid (AA); (ii) by using pure PBA as core material; and (iii) by cross-linking the shell. Particle morphology was characterized by atomic force microscopy (AFM) on freeze-dried and on tempered single particles. The degree of coverage was found to depend on the shell content and the phase compatibility. The results are in good agreement with findings from transmission electron microscopy and solid state NMR given in Acta Polymerica [50 (1999) 347]. The experimental results are compared to predictions from simulation work on the particle morphology based on thermodynamic and kinetic considerations. The second part of the paper focuses on the phase distribution and the film morphology of films formed by the structured particles. Phase distribution at the surfaces, degree of film formation and the phase distribution in the bulk are characterized by AFM, cross-correlated and compared to the findings regarding particle structure in the first part of the paper. This approach is to our knowledge unique regarding its completeness and new in its methodology. The microscopic results concerning the bulk, the single particle and the surface properties are correlated to macroscopic properties like the minimum film forming temperature, pendulum hardness and gloss. : S 0 9 2 7 -7 7 5 7 ( 0 1 ) 0 0 4 9 9 -X
Studies on polymer latex films: I. A study of latex film morphology
Polymer International, 1991
Polymer films have been formed from poly (butyl methacrylate) latices prepared by surfactant-free emulsion polymerisation. The latices having also been cleaned by microfiltration constitute model colloid particles and hence form 'model' films.
Polymer, 2012
Films cast from multiphase polymer particles have the potential to combine the properties of their components synergistically. The properties of the film depend on the hybrid polymer architecture and the film morphology. However, how the polymer microstructure and particle morphology are transformed during film formation to determine the film morphology is not well understood. Here, using waterborne alkyd-acrylic nanocomposite particles in a case study, it was found that phase migration leading to the formation of aggregates occurred during film formation. A coarse-grained Monte Carlo model was developed to account for the effects of polymer microstructure and particle morphology on the morphology of the film. The model was validated by comparing its predictions with the observed effects, and then used to explore combinations of polymer microstructure and particle morphology not attainable with the system used as a case study. Significantly, the morphology of the particles was found to have a greater influence than the compatibility of the phases in determining the film structure.
Silicone–polyacrylate composite latex particles. Particles formation and film properties
Polymer, 2005
Composite latex particles with a polydimethylsiloxane PDMS core and a poly(methyl methacrylate-con -butyl acrylate) P(MMA-BA) copolymer shell were synthesized by seeded emulsion polymerization using the PDMS latex as the seed. The compatibility between the two polymer phases was changed by introducing vinyl groups in the latex core. Monomer conversions and particle size evolution were monitored to see the influence of the nature of the core functionality on the polymerization kinetics and on the extent of secondary nucleation. Particle morphology was characterized by cryo-transmission electron microscopy. The P(MMA-BA) copolymer formed a regular shell around the PDMS seed, whereas nonuniform coatings were formed when vinyl functionalities were introduced into the seed. Films were produced from the latexes, and their surface property was analyzed by X-ray photoelectron spectroscopy and contact angle measurements. It was shown that the PDMS component segregated to the polymer/air interface and that the extent of segregation depended on the original particles structure. Because PDMS has a very low glass transition temperature, it can easily diffuse throughout the film material. However, protected by an acrylic shell, polymer diffusion is significantly hindered and the film then displays all the characteristic properties of the acrylic copolymer. The surface composition of the films formed by the structured particles which PDMS core was not totally covered by the polyacrylate, was found to be intermediate between the composition of the films issued from the core-shell latexes and that of the films produced from blends of pure polyacrylate and PDMS latexes.
Progress in Organic Coatings, 2012
Miniemulsion polymerization offers several advantages over conventional emulsion polymerization to co-polymerize alkoxysilane monomers, which easily undergo premature hydrolysis and condensation reaction into the polymer particles. The premature hydrolysis and the subsequent condensation reaction can lead to colloidal instability. Furthermore, the premature intra-particle cross-linking will reduce the capability of the latex particles to form films. In this paper we discuss the miniemulsion co-polymerization of the butyl acrylate, methyl acrylate and 3-methacryloxypropyltrimethoxysilane BA-MA-MEMO. The latexes features have been characterized and a compressive explanation of the features has been given. Finally, the work focussed on the study of the latex film formation, and mechanical properties by using nanoindentation trials to measure the superficial properties of the film, and also stress-strain curves have been produced.
Latex film performance of styrene-acrylic particles functionalized with acrylic acid
Journal of Applied Polymer Science, 2009
Latex polymers are frequently used as substitutes for solvent-borne coatings in environmental friendly technologies. However, the relationship between the copolymer composition and the latex film performance must be established. The preparation of a series of styrene-n-butyl acrylate latexes functionalized with different amounts of acrylic acid through semicontinuous emulsion polymerization is presented. In this work, latexes were employed to study the modification of the latex film prop-erties by the addition of acrylic acid during the polymerization; mainly, the adhesion to the substrate, the water vapor permeability, and the electrical film resistance were examined. The most advantageous acrylic acid content was established by a balance of the tested properties.