Influence of chemical composition on the rheological behavior of condensation reaction resins.: An article from: Polymer Engineering and Science
Book Details
PublisherSociety of Plastics Engineers, Inc.
ISBN / ASINB0008DATW8
ISBN-13978B0008DATW8
AvailabilityAvailable for download now
Sales Rank13,299,176
MarketplaceUnited States 🇺🇸
Description
This digital document is an article from Polymer Engineering and Science, published by Society of Plastics Engineers, Inc. on February 1, 2003. The length of the article is 4269 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.
From the author: In this paper, the chemorheological and dynamic mechanical behavior of melamine-formaldehyde (MF) resins of four different formaldehyde/melamine (F/M) molar ratios (1.25, 1.5 1.75 and 2.00) are Investigated. ME resins polymerize via a polycondensation reaction involving formation of up to 10 wt% of [H.sub.2]O on cure. This typically results in rapid and extensive foaming of the resin when it is cured under atmospheric pressure. Experimental adaptation for the foaming behavior of ME resins is used to gather rheological Information concerning the curing kinetics and the mechanical response of neat ME resins of different molar ratios. Likewise, the procedures developed allow curing of the resins under atmospheric pressure, hence allowing volatile evacuation as occurs during venting procedures (commonly used during compression molding of ME molding compounds) or as a result of absorption by hydrophilic fillers or substrates. The results show that increased moisture content in the B-stage leads to faster reaction rates and greater foaming. Gelation and vitrification times are identified for each molar ratio, and are found to increase with decreasing molar ratio. The dynamic mechanical behavior of carefully molded neat ME samples of different molar ratios is studied using DMTA. [T.sub.g] is found to be 200[degrees]C for the resin with the lowest formaldehyde content (F/M = 1.25), and around 230[degrees]C for the other resins. The storage shear modulus above [T.sub.g] is studied, and the results show that the crosslink density increases with increasing molar ratio.
Citation Details
Title: Influence of chemical composition on the rheological behavior of condensation reaction resins.
Author: M. Doyle
Publication:Polymer Engineering and Science (Refereed)
Date: February 1, 2003
Publisher: Society of Plastics Engineers, Inc.
Volume: 43 Issue: 2 Page: 297(9)
Distributed by Thomson Gale
From the author: In this paper, the chemorheological and dynamic mechanical behavior of melamine-formaldehyde (MF) resins of four different formaldehyde/melamine (F/M) molar ratios (1.25, 1.5 1.75 and 2.00) are Investigated. ME resins polymerize via a polycondensation reaction involving formation of up to 10 wt% of [H.sub.2]O on cure. This typically results in rapid and extensive foaming of the resin when it is cured under atmospheric pressure. Experimental adaptation for the foaming behavior of ME resins is used to gather rheological Information concerning the curing kinetics and the mechanical response of neat ME resins of different molar ratios. Likewise, the procedures developed allow curing of the resins under atmospheric pressure, hence allowing volatile evacuation as occurs during venting procedures (commonly used during compression molding of ME molding compounds) or as a result of absorption by hydrophilic fillers or substrates. The results show that increased moisture content in the B-stage leads to faster reaction rates and greater foaming. Gelation and vitrification times are identified for each molar ratio, and are found to increase with decreasing molar ratio. The dynamic mechanical behavior of carefully molded neat ME samples of different molar ratios is studied using DMTA. [T.sub.g] is found to be 200[degrees]C for the resin with the lowest formaldehyde content (F/M = 1.25), and around 230[degrees]C for the other resins. The storage shear modulus above [T.sub.g] is studied, and the results show that the crosslink density increases with increasing molar ratio.
Citation Details
Title: Influence of chemical composition on the rheological behavior of condensation reaction resins.
Author: M. Doyle
Publication:Polymer Engineering and Science (Refereed)
Date: February 1, 2003
Publisher: Society of Plastics Engineers, Inc.
Volume: 43 Issue: 2 Page: 297(9)
Distributed by Thomson Gale
