Untitled

Feldman, D.

doi:10.1023/a:1021148205366

Cited by 343 publications

(119 citation statements)

References 21 publications

Supporting

Mentioning

118

Contrasting

Order By: Relevance

“…At the surface region oxygen reacts with the radicals on the PAA (Scheme 2) which undergoes further reactions leading to chain scission and finally, the production of low molecular weight volatile components. 26 In the interior there is minimal oxygen and chemical crosslinking is the dominant process (Scheme 3). In contrast, in the nitrogen atmosphere chemical crosslinking at both the surface and the interior is the dominant process.…”

mentioning

confidence: 99%

Crosslinking neat ultrathin films and nanofibres of pH-responsive poly(acrylic acid) by UV radiation

et al. 2010

View full text Add to dashboard Cite

Electrospun polyelectrolyte hydrogel nanofibres are being developed for many applications including artificial muscles, scaffolds for tissue engineering, wound dressings and controlled drug release. For electrospun polyelectrolytes, a post-spinning crosslinking process is necessary for producing a hydrogel. Typically, radiation or thermal crosslinking routines are employed that require multifunctional crosslinking molecules and crosslink reaction initiators (free radical producers). Here, ultraviolet subtype-C (UVC) radiation was employed to crosslink neat poly(acrylic acid) (PAA) nanofibres and films to different crosslink densities. Specific crosslink initiators or crosslinking molecules are not necessary in this fast and simple process providing an advantage for biological applications. Scanning probe microscopy was used for the first time to measure the dry and wet dimensions of hydrogel nanofibres. The diameters of the swollen fibres decrease monotonically with increasing UVC radiation time. The fibres could be reversibly swollen/contracted by treatment with solutions of varying pH, demonstrating their potential as artificial muscles. The surprising success of UVC radiation exposure to achieve chemical crosslinks without a specific initiator molecule exploits the ultrathin dimensions of the PAA samples and will not work with relatively thick samples. Crosslinking neat ultrathin films and nanofibres of pH-responsive poly(acrylic acid) by UV radiation Adrian Gestos, Philip G. Whitten, Geoffrey M. Spinks * and Gordon G. Wallace Electrospun polyelectrolyte hydrogel nanofibres are being developed for many applications including artificial muscles, scaffolds for tissue engineering, wound dressings and controlled drug release. For electrospun polyelectrolytes, a post-spinning crosslinking process is necessary for producing a hydrogel. Typically, radiation or thermal crosslinking routines are employed that require multifunctional crosslinking molecules and crosslink reaction initiators (free radical producers). Here, ultraviolet subtype-C (UVC) radiation was employed to crosslink neat poly(acrylic acid) (PAA) nanofibres and films to different crosslink densities. Specific crosslink initiators or crosslinking molecules are not necessary in this fast and simple process providing an advantage for biological applications. Scanning probe microscopy was used for the first time to measure the dry and wet dimensions of hydrogel nanofibres. The diameters of the swollen fibres decrease monotonically with increasing UVC radiation time. The fibres could be reversibly swollen/contracted by treatment with solutions of varying pH, demonstrating their potential as artificial muscles. The surprising success of UVC radiation exposure to achieve chemical crosslinks without a specific initiator molecule exploits the ultrathin dimensions of the PAA samples and will not work with relatively thick samples.

show abstract

mentioning

confidence: 99%

Crosslinking neat ultrathin films and nanofibres of pH-responsive poly(acrylic acid) by UV radiation

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Under outdoor weatbering exposure, ultraviolet radiation (UV) exposure and the combined function of heat and moisture (hydrothermal effects) are the two most critical factors contdbuting to degradation [32][33][34][35][36][37]. In the present study, the coating degradation due to UV is a pdme concem for polyurethane topcoat, but has little effect to its underlying epoxy primer, because this layer is never normally exposed to UV.…”

Section: B Coating Failure Environmentmentioning

confidence: 92%

Impact of Mechanical Strain Environment on Aircraft Protective Coatings and Corrosion Protection

Tiong

Clark

2011

Journal of Aircraft

View full text Add to dashboard Cite

Aircraft paint schemes (paint and sealant) are a key element of corrosion preventive measures, and ensuring that sueh schemes and other coatings are effective and durable under service conditions is essential If corrosion eosts and maintenance costs are to be minimized. Coatings can degrade under the influence (if environmental factors sueh as exposure to moisture, high temperature, ultraviolet radiation, and so forth. Coaling failure is often particularly evident at joints, and while failure may be accelerated in some regions hy local variations in coating thickness and geometry at features sueh as edges, or by erosion, it is likely that the displacements which oeeur at these locations under service loads will he a eontrihuting factor. The impact of in-serviee mechanical loading on coating degradation has so far received little attention, despite clear evidence that coatings tend to fail Hrst at specific sites sueh as sheet ends and around fastener heads. This paper argues that the magnitude of the applied service loads and the nature of the load history should be considered in predicting and assessing rates of eoating degradation, and that development of a thermomeehanieal history is a more appropriate approaeh. The likely impaet of joint displacements on the protection of aging aircraft is also discussed. Nomenclature it "( D E, e (', I. r k t '• It) ß Al* e* £/, e", fí «ihCo (Ta = crack length/depth, tntn = critical intertacial delamination length, tnm = diameter of fastener shank, mm = elastic tnodulus of coating, MPa = edge margin, mm = critical energy release of coating, i/nr = spacing between two perpendicular cracks in the coating, mm = effective length of coating, mm = critical stress intensity factor, MPa (m)''' = critical buckling stress constant = thickness of sheet, tnm = thickness of coating, mm = width of the sheet = initial postbuckling slope = geometry factor = change of effective length, mm = strain at the bottom surface of the plate = hygroscopic strain = mechanically-induced strain = strain at the top surface of the plate = thermally-induced strain = compressive residual stress, MPa = critical tensile stress, MPa = Pois.son's ratio of coating

show abstract

“…Particularly when exposed to UV radiation and in the presence of oxygen, polyolefins undergo a photo-oxidative process, whose intensity can range from a superficial change, damaging the aesthetics of the product, to significant structural modifications, affecting their physical and mechanical properties [1,2] . The addition of hindered amine light stabilizers (HALS) to a polymer is the most effective way to stabilize it against UV radiation.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and photostabilizing performance of a polymeric HALS based on 1,2,2,6,6-pentamethylpiperidine and vinyl acetate

2015

View full text Add to dashboard Cite

Untitled

Cited by 343 publications

References 21 publications

Crosslinking neat ultrathin films and nanofibres of pH-responsive poly(acrylic acid) by UV radiation

Crosslinking neat ultrathin films and nanofibres of pH-responsive poly(acrylic acid) by UV radiation

Impact of Mechanical Strain Environment on Aircraft Protective Coatings and Corrosion Protection

Synthesis and photostabilizing performance of a polymeric HALS based on 1,2,2,6,6-pentamethylpiperidine and vinyl acetate

Contact Info

Product

Resources

About