Improving the performance of urea‐formaldehyde wood adhesive system using dendritic poly(amidoamine)s and their corresponding half generations

Essawy, Hisham; Moustafa, Abd-Allah B.; Elsayed, Nadia H.

doi:10.1002/app.30696

Cited by 34 publications

(31 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…21,22 Amidation of the resulting esters in a subsequent step with ethylenediamine gives another subunits. Completion of this sequence leads to a full generation with amine terminals (Gn-NH 2 ).…”

Section: Resultsmentioning

confidence: 99%

Poly(amidoamine) dendritic structures, bearing different end groups, as adhesion promoters for urea–formaldehyde wood adhesive system

Essawy¹,

Mohamed²

2010

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

A series of core-shell poly(amidoamine) (PAMAM) dendritic compounds bearing different end groups such as AOH, NH 2 , and NH 3 þÀ Cl up to the third generation were prepared via successive Michael addition of a nucleophilic core (ethylenediamine) to methylacrylate followed by amination steps using ethylenediamine for the amine-terminated while ethanolamine for the hydroxyl-terminated compounds, also the protonated ammonium salt terminated form was obtained by cationization of the amine-terminated form using hydrochloric acid solution. The Surface activity and aggregation behavior of the corresponding aqueous solutions of the prepared generations with their different end groups were studied and confirmed by surface tension measurements using ring method technique. The prepared dendrimers showed high surface activity and the measurements revealed their ability to self aggregate in water at very low concentrations, critical aggregation concentrations (CACs). The CACs were found to decrease with increasing the generation number, which implies that molecular weight and structure play important rules in controlling the surface activity and CAC. The dendritic compounds proved to be effective as adhesion promoters for urea formaldehyde (UF) resins when applied as wood adhesive systems, which was ascribed in partial to the improved wetting over the substrate, a role that is fundamentally related to the huge number of function groups present at the interface.

show abstract

Section: Resultsmentioning

confidence: 99%

Poly(amidoamine) dendritic structures, bearing different end groups, as adhesion promoters for urea–formaldehyde wood adhesive system

Essawy¹,

Mohamed²

2010

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

show abstract

“…In brief, this hyperbranched polymer, HB(MA-EDA)3, was not suitable for the modification of UF resins as particleboard binders, at least when it was added as a final additive. This may imply the necessity for starting the modification of UF resins with this modifier in the early steps of the resin preparation to ensure effective insertion into the network structure (Essawy et al 2009;2010;Essawy and Mohamed 2011). To enhance the water resistance of the MUF resin, these reactive PAMAMs were also used as additives to adjust the pH at the end stage instead of using sodium hydroxide, as in a previous study (Amirou et al 2014).…”

Section: Resultsmentioning

confidence: 99%

“…The highly branched and three-dimensional architecture of these macromolecules have attracted considerable attention in the past few decades (Uhrich et al 1992;Frechet 1994;Inoue 2000). In addition to numerous applications in various fields such as medicine, chemistry, materials science, biology, and physics, there is interest in the use of dendrimers as modifiers for wood adhesives (Essawy et al 2009;2010;Essawy and Mohamed 2011;Zhou et al 2013;. The dendritic poly(amidoamine)s (PAMAMs) are among the most widely used dendrimers as a result of their ready commercialization.…”

Section: Introductionmentioning

confidence: 99%

“…Full, as well as half, of the generations of dendritic PAMAMs have been introduced into a UF wood adhesive system as modifiers (Essawy et al 2009), revealing that PAMAMs are reactive modifiers for the UF wood adhesive system and can increase the stability of the UF resin and enhance the performance of the bonded wood joints. In addition, a series of core-shell PAMAM dendritic compounds bearing different end groups such as -OH, -NH2, and NH3 +-Cl up to the third generation have been used as modifiers for UF resins (Essawy and Mohamed 2011).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hyperbranched Poly(amidoamine)s as Additives for Urea Formaldehyde Resin and Their Application in Particleboard Fabrication

Zhang¹,

Amirou²,

Essawy³

et al. 2014

BioResources

Self Cite

View full text Add to dashboard Cite

Three types of hyperbranched poly(amidoamine)s (PAMAMs), namely HB(MA-EDA)1, HB(MA-EDA)3, and HB(MA-DETA)1.2, were synthesized and used as modifiers for urea-formaldehyde (UF) resin. Particleboards bonded with these modified UF resins were fabricated and evaluated. The results showed that these PAMAMs caused some adverse effects on UF resin performance. The main problems of PAMAMs were their high buffer capacity and high pH values, which are attributed to the peripheral amino groups at the terminals, both of which had a serious negative influence on UF resin curing. These findings were supported by the gel time measurements in parallel with a predictive investigation on the resins using thermomechanical analysis (TMA). The gel time was prolonged, and the maximum modulus of elasticity (MOE) values decreased with the addition of HB(MA-EDA)3. The use of a strong acid curing agent (HCOOH) could reduce the gel time into a normal range; however the performance of the corresponding particleboards still deteriorated. Therefore, these PAMAMs are considered not suitable for the modification of UF resin when applied as final additives. Beyond all expectations, the modified UF resin that employed very finite amounts of HB(MA-EDA)1 as a pH regulator instead of NaOH yielded a considerable upgrade in performance of the produced particleboards.

show abstract

“…In the literature, it has been shown that hyperbranched molecules can be efficient modifiers for vinylester-urethane hybrid resin (Gryshchuk et al 2002), urea-formaldehyde resins (Essawy et al 2009), or might provide building polyurethane networks when crosslinked with isocyanates (Nasar et al 2003;Okrasa et al 2008). Having in mind that hyperbranched hydroxyl-terminated polyglycerols are highly reactive towards isocyanates, Mamiński et al (2011) recently showed that it was possible to develop fast-curing polyurethane adhesives based on hyperbranched polyglycerols.…”

Section: Introductionmentioning

confidence: 99%

Hyperbranched Polyglycerols With Bisphenol a Core as Glycerol-Derived Components of Polyurethane Wood Adhesives

Mamiński¹,

Szymański²,

Parzuchowski³

et al. 2012

BioResources

View full text Add to dashboard Cite

a Two hyperbranched polyglycerols (HBPGs) and one oligoglycerol containing bisphenol A in the core of the molecule were synthesized from glycerol carbonate and applied as polyols in 2-component polyurethane adhesive systems. It was shown that mechanical performance of the joints made in solid wood depended on the hydroxyl functionality of the polyglycerol as well as on the type of the isocyanate used as a crosslinker. The shear strengths of the best-performing joints exceeded that of the substrate. Eventually, it was proved that hyperbranched polyglycerols might be convenient glycerol-derived raw materials for polyurethane adhesives.

show abstract

Improving the performance of urea‐formaldehyde wood adhesive system using dendritic poly(amidoamine)s and their corresponding half generations

Cited by 34 publications

References 77 publications

Poly(amidoamine) dendritic structures, bearing different end groups, as adhesion promoters for urea–formaldehyde wood adhesive system

Poly(amidoamine) dendritic structures, bearing different end groups, as adhesion promoters for urea–formaldehyde wood adhesive system

Hyperbranched Poly(amidoamine)s as Additives for Urea Formaldehyde Resin and Their Application in Particleboard Fabrication

Hyperbranched Polyglycerols With Bisphenol a Core as Glycerol-Derived Components of Polyurethane Wood Adhesives

Contact Info

Product

Resources

About