Electron Microscopy of Poly(vinyl chlorides) and Ethylene-Vinyl Acetate Rubber Systems

Jyo, Y.; Nozaki, Chieko; Matsuo, Masato

doi:10.1021/ma60022a033

Cited by 24 publications

(8 citation statements)

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“…Similar aspects were observed for other grafted or block copolymers[4]. This permits us t o conclude that t h e obtained copolymers have a branched structure.…”

supporting

confidence: 85%

The copolymerization of the pyrolysis products of polyethylene with styrene

Vasile¹,

Moroi²,

Sabliovschi³

et al. 1986

Acta Polymerica

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Act8 Polymcriu 37 (1986) Nr. 7 41 9 kM is t h e r a t e constant of t h e transfer of reactions t o t h e monomer. N and n as functions of in experiments changeable variables, obtained b y t h e diffusion approach, fully coincide with t h e functions from t h e equations (14) t o (15) i n [4], calculated b y t h e kinetic approach, a n d differ from t h e m by the values of coefficients a n d powers of Dp a n d 8. Hence, t h e experimental data when suitable choosing t h e values are equally described b o t h b y t h e kinetic approach a n d by t h e diffusion approach. As there is a t present n o way of direct determination of b, t h e both approaches m a y b e equally used for t h e description of t h e kinetics of emulsion polymerization in the presence of chain transfer. T h e independence of polymerization rate, noticed i n [lo-111, from t h e ratio of monomer-water in t h e case of emulsion polymerization of vinyl chloride,other conditions being equal, shows, as stated in [8], that t h e rate of escaping for a low weight radical from t h e particle is determined by t h e barrier i n t h e interface of particle-water. This is in favour of t h e kinetic approach. AcknowledgementsThe author wishes t o t h a n k V. M. ORLOVA for t h e preparation of t h e computer program and for t h e solution of t h e series of equations.

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“…Similar aspects were observed for other grafted or block copolymers[4]. This permits us t o conclude that t h e obtained copolymers have a branched structure.…”

supporting

confidence: 85%

The copolymerization of the pyrolysis products of polyethylene with styrene

Vasile¹,

Moroi²,

Sabliovschi³

et al. 1986

Acta Polymerica

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“…The PVC particles seem to contain a 50 to 100 nm broad periferic zone showing radial tracks of EVA indicating a starting disintegration of the particles. Matsuo et al (37) have reported similar radially distributed EVA domains in PVC particles of grafts with 20% EVA-45 (see Fig.32). If the processing temperature of the grafts is increased to 180°C fusion of PVC particles breaks down part of the EVA network to particles of the order of 50 nm (see Fig.31B) DMS showed no effect of grafting on the peak position and width of the EVA phase in PVC/EVA (92.5/7.5) blends processed at 160°C.…”

Section: Svanson and Elmqvist (34) Carried Out Wide Line Nmr Measuremmentioning

confidence: 56%

“…Considering that no slit smearing correction was undertaken these figures seem uncertain. Geil et al (37) do not draw any conclusions from their SAXS curve for unplasticized PVC (see the high scattering intensities at low angles to heterogeneities up to 450 nm and the low intensities at high angles to heterogeneities down to 5 nm and to thermal fluctuations.…”

Section: Figmentioning

confidence: 91%

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Phase structure of polyvinyl chloride (PVC) and PVC/polymer blends

Terselius¹,

Rånby²

1981

Pure and Applied Chemistry

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Commercial PVC is considered as a largely amorphous glassy polymer containing a small fraction of crystalline (ordered) structure. Based on the unique strength of plasticized PVC the presence of a three dimensional network of crystallites is generally accepted. The crystallites consist of a small number of syndiotactically ordered monomer units. The exact size, order and amount of crystallites in PVC is still an open question. The morphology of 'as polymerized" PVCis characterized by free-flowing grains (about lOO,um) containing aggregates of primary particles (about 1 ,um). The existence of subprimary particles are often claimed but the evidence is still controversial. A remaining microheterogeneity after plasticizing with diallylphtalate or ethylene-vinylacetate copolymer with 63 wt-% vinylacetate is, however, indicating the presence of unplasticized nodules or crystallites.The phase structure of PVC blends with acrylo-nitrile-butadiene rubber (NBR), ethylene-vinylacetate copolymer (EVA) and chlorinated polyethylene (CPE) have been elucidated with special reference to the formation of a network structure. The phase structure is shown to depend on compatibility, method of blending and processing temperature at mechanical blending. Thus at increasing compatibility i.e. by increasing the content of acrylonitrile, vinylacetate and chlorine in NBR, EVA and CPE, respectively, the phase inversion of PVC to rubber as continuous phase, is shifted from about 15 to about 2% content of rubber. Increasing the mechanical processing temperature from below to above the critical temperature of primary particle fusion shifts the phase inversion to higher rubber contents (about 30% for non-compatible rubber). At solution blending the inversion is shifted to still higher rubber contents (about 50%). The phase structure of blends with ABS-type of polymers are briefly reported and the possibility of network structure formation is discussed. Finally, blends with crystallizable polymers like polycaprolactone (PCL) and Hytrel (a thermoplastic poyester-ether rubber) are reviewed. The amorphous segments of these polymers are compatible with PVC. PHASE STRUCTURE OF PVCIntroduction PVC has been produced and processed in large volumes for a long time on account of its versatile properties in relation to its low price. Nevertheless, the polymer is still considered "difficult" and its basic properties to a large extent unexplored (1). These problems can be discussed in terms of structure on a molecular,intermolecular and supermolecular level.

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“…The incorporation of EVA-45 (thermoplastic with rubber characteristic) within the matrix of brittle PVC improves the impact resistance enormously; the impact resistance can also be improved by grafting of PVC on EVA (Pevikon A6710). In the grafted copolymer PVC-EVA-45, the EVA domains are evenly distributed in the PVC matrix (6). Grafting increases the adhesion between the phases.…”

mentioning

confidence: 99%

Photodegradation of some poly(vinyl chloride) (PVC) blends: PVC/ethylene‐vinyl acetate (EVA) copolymers and PVC/butadiene‐acrylonitrile (NBR) copolymers

Skowronski

Rabek

Rånby

1984

Polymer Engineering & Sci

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Poly(viny1 chloride) (PVC) and its blends with polybutadieneacrylonitrile (NBR) (containing 2 1.7 weight-percent acrylonitrile (AN), a heterogeneous two-phase system; and containing 41.6 weight-percent of AN, a homogeneous one-phase system) and with polyethylene-vinyl acetate (EVA) (containing 45 weightpercent of vinyl acetate (VA), a heterogenous two-phase system; and containing 65 weight-percent VA, a homogeneous one-phase system) were W-irradiated (at 3500 A W-light (solar spectrum). After W irradiation the kinetics measurements were made of the formation of hydroperoxy (OOH) and carbonyl (CO) groups and the changes of mechanical properties: tensile strength, elongation to break, and impact energy. As a result of the photooxidative degradation of PVC blends, decreases of mechanical properties were observed. The effects are more severe in PVC/NBR blends, which contain unsaturated bonds (polybutadiene segments) than in the case of PVCEVA. The phase structure plays an evident role on the W degradation only of PVC/NBR blends. The photostability of PVC blends can be slightly improved by introducing Tinuvin P or Ni-chelates photostabilizers. PVCIEVA BlendsAddition of 10 parts by weight of EVA-45 (containing 45 weight percent of vinyl acetate) gives a heterogenous two-phase system. EVA domains (weakly polar) are dispersed in the PVC matrix (polar). Addition of EVA-45 component improves impact strength, aging resistance, and weathering performance for outdoor applications (1, 3, 4).Addition of 10 parts by weight of EVA-65 (containing 6.5 weight percent of vinyl acetate) gives a homogeneous one-phase structure, and has a remarkable plasticizing effect on PVC. This is particularly useful in flexible profiles or calendered flexible films,

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Electron Microscopy of Poly(vinyl chlorides) and Ethylene-Vinyl Acetate Rubber Systems

Cited by 24 publications

References 0 publications

The copolymerization of the pyrolysis products of polyethylene with styrene

The copolymerization of the pyrolysis products of polyethylene with styrene

Phase structure of polyvinyl chloride (PVC) and PVC/polymer blends

Photodegradation of some poly(vinyl chloride) (PVC) blends: PVC/ethylene‐vinyl acetate (EVA) copolymers and PVC/butadiene‐acrylonitrile (NBR) copolymers

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