Porosimetry studies on polyacrylic acid-ZnO cements

Padilla, A.; Vázquez, A.; Vázquez‐Polo, G.; Acosta, Dwight; Castaño, V. M.

doi:10.1007/bf00700875

Cited by 13 publications

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“…Exclusion of the finely dispersed porosity might explain the relatively low measured value compared with the glass ionomer cement film. The question of why such fine porosity was observed in the polycarboxylate cement but not in the glass ionomer is difficult to explain, although the existence of fine porosity had been reported previously [3]. The amount of water added to the mix is similar in each case as are the mixing procedures.…”

Section: Discussionmentioning

confidence: 83%

“…A scanning electron microscopic examination of a silver-reinforced glass ionomer restorative cement indicated the presence of pores in this material, together with extensive cracking between the pores, although the latter may have been due to dehydration during sample observation in the SEM [2]. Pore-size distribution in a zinc carboxylate cement has also been investigated by mercury porosimetry [3], which indicated the presence of submicrometre voids ( < 200 nm) only.…”

Section: Introductionmentioning

confidence: 99%

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Porosity in water-based dental luting cements

Bertenshaw

Piddock

1993

J Mater Sci: Mater Med

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The porosity in glass ionomer, zinc polycarboxylate and zinc phosphate dental cements has been studied using an optical microscopic technique. Pores of approximately 20 I~m diameter were observed in all three materials. In addition, finer pores were seen in zinc oxidecontaining cements. It has been postulated that the larger pores are due to entrapment of air during mixing and the finer porosity results from loss of excess water. The deleterious effects of such porosity are discussed.

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Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Porosity in water-based dental luting cements

Bertenshaw

Piddock

1993

J Mater Sci: Mater Med

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“…A ZnO/PAA ratio of 0.6 resulted in minimal porosity. [22] Besides good physical properties, such formulations also have good adhesion properties, e.g., to tooth tissues where Ca 2þ could also Figure 3. Possible modes of bonding of Zn 2þ to carboxylate groups in zinc polycarboxylate cements: a) ionic, b) chelating bidentate, c) asymmetric unidentate, d) bridging bidentate, and e) chelate bidentate (eight-membered ring) (after Nicholson et al [17] ).…”

Section: Chemistry and Materials Properties Of Zinc Ionomersmentioning

confidence: 99%

New Materials for Rapid Prototyping Applications

Stampfl

Liska

2005

Macro Chemistry & Physics

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Why Do We Need New RP Materials?Rapid prototyping (RP) has become a widely used tool for the fabrication and evaluation of physical prototypes during the product development cycle. RP is used since it can produce prototypes with arbitrary shapes quickly and at a lower cost than traditional prototyping techniques. Recently RP has also been investigated regarding its ability to replace traditional mass manufacturing processes in applications where only one or a small number of individually shaped parts is required. Recently, Mühlhaupt and coworkers [1] presented a novel class of materials for RP and the following text will try to emphasize the importance of material developments for future applications of RP technologies.Regarding the type of applications for which the RP models are used, the following groups of prototypes can be distinguished:iii) Visual aids, which serve for visualizing design concepts and evaluate the ergonomics of a prototype. iii) Concept models that provide a certain functionality and are accurate enough to test whether individual parts fit properly within an assembly.iii) Master patterns for tooling and molding processes. iv) Functional parts that can be used to evaluate the functionality of certain parts before they are mass fabricated. Functional models need to fulfill high requirements regarding material quality and shape accuracy. iv) Customized products, which are tailored according to specific requirements of the customer. Customized products are usually made in quantities between one and ten. Applications are mostly in the field of biomedicine, where individual shapes according to a patient's requirements have to be manufactured.The field of visual aids, concept models, and master patterns is traditionally the 'home-ground' of RPs. Most RP processes are optimized for fabricating such prototypes. Since the market for classical prototyping services is saturated and prices for parts offered by RP service bureaus have fallen constantly, [2] the future growth of the RP industry will take place on two levels: i) Low-cost three-dimensional (3D) printers for design bureaus and engineering departments in small and medium-sized companies. These low-cost 3D printers Summary: Rapid prototyping (RP) is a widely used manufacturing tool in the product development cycle. This Highlight article gives a brief overview of the currently available RP techniques with special emphasis on three-dimensional (3D) printing. The advantages and drawbacks of various RP processes regarding material quality, feature resolution, and surface quality are pointed out. New developments in the field of material development allow the use of polymer ionomers for 3D printing. Using polymer ionomers some of the drawbacks of 3D printing can be eliminated. In particular, the mechanical strength can be increased compared to traditional powder systems used for 3D printing. This article describes the chemical background of polymer ionomers and the relevance of these materials for future developments in RP. Cellular structures made...

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“…22 For instance, the chemical interaction between polyacrylates and ZnO has been reported to be preferential. [25][26][27] Poly(acrylic acid) (PAA) molecules preferentially adsorb on the nonpolar facet of ZnO forming coordinative bonds between the carboxylic acid groups and Zn-atoms. 27 The photocatalytic activity of pure ZnO has been recently associated with polar facets.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the modification of their functional groups (‐COOH) could lead to selective sorption matrices . For instance, the chemical interaction between polyacrylates and ZnO has been reported to be preferential . Poly(acrylic acid) (PAA) molecules preferentially adsorb on the nonpolar facet of ZnO forming coordinative bonds between the carboxylic acid groups and Zn‐atoms .…”

Section: Introductionmentioning

confidence: 99%

Surface modification and immobilization in poly(acrylic acid) of Ag/ZnO for photocatalytic degradation of endocrine‐disrupting compounds

Jasso-Salcedo

Meimaroglou

Hoppe

et al. 2016

J of Applied Polymer Sci

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Silver‐modified ZnO particles (Ag/ZnO) are effective catalysts for the photodegradation of water pollutants such as bisphenol‐A. However, until now, their use in continuous processes was back‐drawn because of difficulties associated with their recovery. To overcome this problem, the present work aimed at immobilizing Ag/ZnO in cross‐linked poly(acrylic acid) ‐PAA‐. Ag/ZnO was first silanized using (3‐glycidyloxypropyl)trimethoxysilane and thoroughly dispersed in a water‐acrylic acid solution. The suspension was then submitted to radical polymerization in presence of a cross‐linker (N,N′‐Methylenebisacrylamide). The resulting composites were characterized in terms of chemical structure, morphology, crystallinity, thermal properties, and photostability. Their analyses showed that the silanized particles were chemically anchored to PAA and homogeneously distributed in the matrix. UV‐assisted photocatalysis of bisphenol‐A aqueous solutions showed that immobilized Ag/ZnO can achieve photodegradation performances comparable to pure Ag/ZnO and allows its use in successive cycles and, consequently, in continuous processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43528.

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Porosimetry studies on polyacrylic acid-ZnO cements

Cited by 13 publications

References 0 publications

Porosity in water-based dental luting cements

Porosity in water-based dental luting cements

New Materials for Rapid Prototyping Applications

Surface modification and immobilization in poly(acrylic acid) of Ag/ZnO for photocatalytic degradation of endocrine‐disrupting compounds

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