Surface derivatization of hydroxyl functional acrylic copolymers for characterization by x-ray photoelectron spectroscopy

In this study, methacrylic acid (MAA) and acrylic acid (AA) were photografted onto the ultrahigh molecular weight polyethylene (UHMWPE) plates at different monomer concentrations and temperatures, and the grafted UHMWPE plates were bonded with aqueous polyvinyl alcohol (PVA) solutions. The tensile shear adhesive strength of both grafted UHMWPE plates was also discussed in relation to wettability and water absorptivity. The location of failure was also estimated by X-ray photoelectron spectroscopy (XPS). Wettability of the MAA-grafted UHMWPE plates became constant, when the UHMWPE surface was fully covered with grafted PMAA chains. Conversely, wettability of the AA-grafted UHMWPE plates passed through the maximum value and then gradually decreased against the grafted amount probably due to aggregation of grafted PAA chains. Water absorptivity of the grafted layers formed at lower monomer concentrations or temperatures sharply increased at lower grafted amounts. The adhesive strength increased with the grafted amount and substrate breaking was observed at higher grafted amounts, indicating that a main factor to increase the adhesive strength is the formation of a grafted layer by shorter grafted polymer chains and/or the restriction of the location of photografting to the outer surface region. In addition, surface analysis by XPS showed that failure occurred in the boundary between the layer composed of grafted polymer chains and PVA chains and the ungrafted layer at a low adhesive strength, and the location of failure was shifted to the grafted layer containing PVA chains at the grafted amount increased. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40133.

Section: Surface Analysis Of Failed Surfacesmentioning

confidence: 83%

Section: Water-absorptivity Measurements Of the Grafted Layersmentioning

confidence: 99%

Adhesion of ultrahigh molecular weight polyethylene plates photografted with hydrophilic monomers and evaluation of failure location by X‐ray photoelectron spectroscopy

Yoshida

Mochizuki

Yamada

2013

“…However, the trifluoroacetate moiety were preferentially oriented into the bulk of trifluoroacetylated methyl methacrylate-hydroxypropyl methacrylate copolymers away from the surface, as evidenced by ESCA analysis. 24 These results given in the literatures may suggest that the CF3 bond polarity plays important role to control their surface structure, depending on copolymers and sequence length.…”

Section: Esca Analysis Of Solution-cast Filmsmentioning

confidence: 86%

Surface characteristics of fluoroalkylsilicone—poly(methyl methacrylate) block copolymers and their PMMA blends

Inoue

Matsumoto

Matsukawa

et al. 1990

SynopsisSurface properties of fluoroalkylsilicone-poly ( methyl methacrylate) block copolymers and their poly(methy1 methacrylate) (PMMA) blends have been intensively studied to draw a relationship between surface segregation behavior and adhesion performance. The fluoroalkylsilicone-PMMA block copolymers containing three kinds of fluoroalkyl side chains (i.e., 3,3,3-trifluoropropyl) ( CF3CH2CH2-, abbreviated as TFP), tridecafluoro-1,1,2,2-tetrahydrooctyl[ F3C ( CF2) TFO] , and heptadecafluoro-1,1,2,2-tetrahydrodecyl groups [ F3C ( CF2)$H2CH2-, HFD] on the siloxane chains were prepared according to the macroazoinitiator method. Contact angle measurement and X-ray photoelectron spectroscopy (or ESCA) were used to obtain structural information on the surface of the solution-cast films. A significant effect of fluoroalkyl groups on the surface accumulation not only in silicon but also fluorine atoms were observed for relatively long fluoroalkyl side chains (i.e., TFO and HFD) . On the contrary, TFP group was found to be effective to orient to the hydrophilic surfaces (i.e., glass-side surfaces). The surface accumulation of fluoroalkyl groups in the films was also reflected by the 180' peel strength against pressure-sensitive adhesives as a measure of the adhesion performance. These results indicated that incorporation of relatively long fluoroalkyl groups much enhanced the surface hydrophobicity (and/or oleophobicity ) of solutioncast films in addition to that of the siloxane-enriched surfaces. The composition and orientation of the functional groups on the surface were also speculated based on ESCA data. INTRODUCTIONSurface segregation behavior of block copolymers are of very much interest in fields of adhesion, coating, printing, friction, biocompatibility and so on.It was reported in previous papers1" that the polysiloxane segments of polydimethylsiloxane-poly ( methyl methacrylate) block copolymers ( PDMS-b-PMMA ) derived from poly ( azo-containing siloxaneamides ) (abbreviated as PASAs) and their PMMA blends (PDMS-b-PMMA/PMMA) were accumulated on air-side surfaces of the solution-cast films as revealed by water contact angle measurements and ESCA (electron spectroscopy for chemical analysis) or X-ray photoelectron spectroscopy. It was concluded that the most flexible polydimethylsiloxane segments were readily phase-separated and moved to the top most surface because of their low surface energy. In those works, a significant effect of siloxane chain length (SCL) on the surface accumulation behavior of the siloxane segments was also emphasized. The preferential surface accumulation of the siloxane segments resulted in a steep decrease in peel strength Journal of Applied Polymer Science, Vol. 40, 1917-1938 (1990 It was also noticed that the siloxane surface segregation substantially depended on the block length of siloxane chain (i.e., siloxane chain length (SCL) ) , and the rate to attain an equilibrium surface. The latter was an important factor for surface segregation, as revealed from the difference of t...

“…The measured binding energies were adjusted to C1s ϭ 285.0 eV or Au4f 7/2 ϭ 83.8 eV. 12,13 The ratio of the two intensities, i and j, measured under identical conditions (i.e., the intensity ratio) is given by…”

Section: Surface Compositions and Hydrophilic Propertiesmentioning

confidence: 99%

Improvement in adhesive‐free adhesion by the use of electrostatic interactions between polymer chains grafted onto polyethylene plates

Kojima¹,

Yamada²,

Fujii³

et al. 2006

ABSTRACT:The tensile shear adhesive-free adhesion properties induced by electrostatic interactions between poly(acrylic acid) (PAA) and poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) chains grafted onto polyethylene (PE) with low-density (LDPE) or high-density (HDPE) plates were studied. PAA-or PDMAEMA-grafted PE plates were immersed in a HCl or NaOH solution or water for 24 h, and their electrostatic properties were changed before they were overlapped with each other and heat-pressed. The breaking of the substrate between the two plates with waterswollen grafted layers was observed in the low range of grafted amounts in comparison with immersion in the acidic and basic solutions. The ability of the two plates with grafted polymer chains swollen in water to strongly bond with each other was a result of electrostatic interactions formed by positively charged PDMAEMA and negatively charged PAA chains. The breaking of the substrate in the case of adhesive-free adhesion between quaternized PD-MAEMA-grafted and PAA-grafted PE plates immersed in the basic solution occurred with lower grafted amounts of PAA. This came from the strong attractive force between dissociated anionic PAA chains and quaternized cationic PDMAEMA chains in the basic solution. In addition, the adhesive-free adhesion strength of HDPE plates with the same grafted polymer chains encountered the breaking of the substrate with lower grafted amounts than that of LDPE plates. It was concluded that the grafting of polymer chains onto HDPE plates with high crystallinity was considerably restricted to the outer surface regions.