Carboxyl reactive liquid polymer

Reaction products of solid epoxy resins, e.g., DER 664 (Dow), and Hycar carboxyl reactive liquid polymers can be used to toughen solid epoxy resins for use in powder adhesives or coatings (see Table 4). 

Technical Literature on Hycar Carboxyl Reactive Liquid Polymers, The BFGoodrich Chemical Co. 

Caiboxyl reactive liquid polymers (CRLP) are chemically reactive with epoxy resins and capable of chain extension and crosslinking through the carboxyl groups. The reactions most important in adhesive applications are those with epoxide groups and with aliphatic hydroxyl groups. A list of several commercially available CRLP products is shown in Table 2. 

Elastomeric modifiers are used to increase the peel strength (toughness) of epoxy resin adhesives. The most commonly used elastomeric materials are functionally terminated polybutadiene resins made by the B.F. Goodrich Company, Chemical Group under the trade name of Hycar Reactive Liquid Polymers. Initially, carboxyl-terminated butadiene acrylonitrile (CTBN) resins were introduced the carboxyl terminated materials are usually adducted with the epoxy resin to improve compatibility and to increase the toughness. 

Later, in 1974, amine reactive versions of the liquid nitrile polymers (ATBN) were issued, thereby offering another way to introduce rubbery segments into a cured epoxy resin network. References are cited which provide detailed discussions of nitrile rubber, carboxylic nitrile rubber and both carboxyl- and amine-terminated nitrile liquid polymers (1-4). Table I illustrates CTBN and ATBN products structurally. Table II provides properties for typical solid carboxylic nitrile elastomers. 

The use of elastomeric or flexibilizing modifiers occurred and grew with epoxy resins first. Various aspects of toughened epoxy adhesives have been covered in reviews by the present authors (2,3), where the elastomeric modifiers have essentially been carboxylic, liquid and solid butadiene/acrylonitrile polymers. There has not been a systematic review, however, of these and other reactive liquid polybutadiene/acrylonitriles in the burgeoning areas of acrylic, anaerobic and radiation-curable systems. Thus, this paper s intent. 

The novel liquid polymers are characterized by having reactive terminal vinylidene groups and are prepared from liquid carboxyl-terminated polybutadiene polymers using an amine catalyst [50]. 

These acids can be used alone or as mixtures. It is especially advantageous to use a mixture of liquid and gaseous acids. The gaseous acid will stabilize free monomer in the headspace of a container, while the liquid acid will prevent premature polymerization of the bulk monomer or adhesive. However, it is important to use only a minimum amount of acid, because excess acid will slow initiation and the formation of a strong adhesive bond. It can also accelerate the hydrolysis of the alkyl cyanoacrylate monomer to 2-cyanoacrylic acid, which inhibits the polymerization of the monomer and reduces molecular weight of the adhesive polymer. While carboxylic acids inhibit the polymerization of cyanoacrylate monomer, they do not prevent it completely [15]. Therefore, they cannot be utilized as stabilizers, but are used more for modifying the reactivity of instant adhesives. 

This work concerns mainly the modification of commercial polymers bearing hydroxy fonctions as alcohol, hydroperoxide or carboxylic acid, by reactive gases or liquid volatil compounds capable to penetrate in the polymer matrix. The modifications of membranes properties as gas permeability or surface tension will also be reported. Few examples will also concern the reaction of double bond with 12 and HBr vapor as well as the oxidation of piperidine group by peracetic acid. 

Gopakumar et al. [10] reported the in situ compatibilization of poly(phenylene sulfide) (PPS)/wholly aromatic thermotropic liquid crystalline polymer (TLCP) Vectra A950 blends by reactive extrusion. The authors prepared the in situ compatibilized PPS/TLCP blends in a twin-screw extruder by reactive blending of PPS and TLCP in the presence of dicarboxyl-terminated poly(phenylene sulfide) (DCTPPS). Block copolymer was formed during reactive blending, by transesterification reaction between carboxyl... 

With the aim of elaborating polymers with an anisotropic columnar structure and containing a quantitative ratio of metal centers incorporated to study their optical properties, in situ polymerization of reactive low-molar-mass liquid crystals oriented in their mesophase has been developed. Cu, Mg, and Zn carboxylates bearing terminal acrylate functions and their subsequent... 

In this section, the blocking of the amine end groups of PA-6 with liquid diketene (the dimer of ketene) and the diketene acetone adduct (Fig. 13.8) in supercritical CO2 is discussed. Ketene itself is an extremely reactive, unstable, and very toxic gas. Diketene and the diketene acetone adduct have frequently been used in industry since they are reactive toward a large variety of functional groups such as amines, alcohols, and carboxylic adds [83-85], but are not reactive toward the amide groups in the PA-6 chain without a catalyst, whereas ketene is. This makes them useful for the modification of polymer partides in supercritical CO2 under very mild reaction conditions, thereby avoiding side reactions. 

From the very beginning to date dicyclohexylcarbodiimide [89] has been by far the most utilized reagent to activate N-protected amino acids, because of its convenience in use and its very suitable reactivity. Usually the carboxylic component and the lipophilic diimide in equimolar portions are admixtured to the polymer-bound amino component in a three to fivefold excess, in most cases dissolved in dichloromethane, which was found not to favor racemization and to suppress other side reactions during activation. To approach, as closely as possible, the desired complete transformation on polymer, the dissolved compounds are introduced in high concentrations so that the volume depends solely on the swelling rate of the gel phase, which has to be well suspended in the reaction liquid. 

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