Preparation and characterization of heterophase blends of polycaprolactam and hydrogenated polydienes

Abstract

SynopsisThe preparation, analysis, testing, and structure determination of ultrahigh impact rubbertoughened polycaprolactams (nylon 6) are described. Partially unsaturated hydrocarbon rubbers were used for this purpose. They were functionalized by reaction either in solution or in bulk with maleic anhydride to give rubbery "ene" adducts containing varying amounts of pendent succinic anhydride. Tough, rigid, thermoplastic engineering resins with notched Izod impact strengths of 750-1000 J/m were prepared by briefly melt-blending these adducts with nylon 6. Properties of the blends could be affected by the type and amount of elastomer used, the anhydride content, the type of nylon, the mixing conditions and the test conditions. Fractionation by coacervation in m-cresol/cyclohexane of a typical resin containing 20% by weight of functionalized rubber showed approximately 35% of a rubber-nylon graft, along with a few percent of free rubber dispersed in the nylon 6 matrix. A comb-block copolymer structure for the graft and a model for its formation are proposed, consistent with analyses of the fractions. Some of the blends prepared with partially hydrogenated medium vinyl polybutadiene-maleic anhydride adducts displayed a retention of impact properties at low temperatures which was superior to that obtainable with a similarly prepared EPDM-modified nylon 6. Transmission electron microscopy of a blend containing an anhydride-modified hydrogenated medium vinyl polybutadiene showed a morphology consisting of a nylon matrix containing finely dispersed, irregularly shaped, 0.03-0.55 pm rubber domains in which were found even smaller domains of nylon. INTRODUCTIONIn the unmodified state polycaprolactam, nylon 6, resin has a sufficient combination of good tensile and flexural properties, high heat distortion temperature, and an appreciable notched Izod impact strength on the order of 50 J/m that it is considered to be among the first "engineering resins." By chemically grafting the nylon to a dispersed rubber, heterophase blends with impact strengths on the order of lo00 J/m, well in exces of so-called "high impact" resins, can be obtained, and the blends might be more properly named " ultra-high impact" resins.Toughened blends of nylon 6 were prepared in 1974 by Ide and Hasegawa,' who recognized that the dispersion of polypropylene in nylon 6 was improved when the PP was first functionalized by grafting with maleic anhydride. They 2332LAWSON, HERGENROTHER, AND MATLOCK attributed this to the presence of an interfacial agent which was formed through the reaction of the anhydride with amine chain ends. The impact strengths of their blends approached ca. 250-325 J/m. Blends of nylon 6 and rubber which show toughening have been described by Cimmino et a1.,2 Martuscelli et al.,3 and G r e~o .~ In these reports, the blends were prepared from nylon 6 and an EPM copolymer grafted with maleic anhydride in the presence of peroxide; in some cases the blends were prepared by the in s i b polymerization of caprolactam in the presence of ...

On Toughness and Stiffness of Poly(butylene terephthalate) with Epoxide‐Containing Elastomer by Reactive Extrusion

“…The morphology of PBT/E-MA-GMA blends shown here closely resembles those of other polymer/rubber blends having low toughness. [26][27][28][29][30] With increasing E-MA-GMA content, there is a complete change in the fracture morphology, from brittle ( Figure 8 (Figure 9a), which resemble but not identical to those of fast fracture in glassy polymers. Each parabolic marking contains a flaw or heterogeneity at the locus at which the secondary fracture seems to have initiated.…”

Rubber toughening of glass fiber reinforced nylon‐6,6 with functionalized block copolymer SEBS‐g‐MA

“…From a previous study 30 on toughening PA-6 with partially unsaturated rubbers, which were functionalized with maleic anhydride, it was found that the blends consist of about 35% of a rubber-g-nylon comb-block copolymer. Our results seem to be in agreement with this since in spectrum c the characteristic peaks of maleic anhydride groups were still detected.…”

Blendas de poliamida 6/elastômero: propriedades e influência da adição de agente compatibilizante

“…Percentagem de nitrogênio em diferentes amostras, determinadas por análise elementar CHN binária PA6/EPDM em relação à blenda PA6/EPDM/EPDMg-AM deve-se provavelmente a fraca adesão entre as fases. Os diâmetros dos domínios em blendas binárias com pequenas quantidades de EPDM-g-AM com um grau de enxerto de anidrido maleico de 1,7%, são da ordem de 0,03 a 0,60 µm, faixa considerada ideal para obtenção de materiais tenazes [18] . Entretanto, valores de resistência ao impacto Izod superiores ao valor correspondente a PA6 foram obtidos para as blendas PA6/EPDM-g-AM.…”