An attempt was made to study the effect of interfacial slippage on the filler reinforcement based on the boundary condition that the constituents of a particle‐filled composite can slip relative to each other, but no cavities are formed at the interfaces. The elastic field satisfying these conditions is derived using the linear theory of elasticity and the effective elastic moduli of the composite are calculated. The following assumptions are made: (1) Filler particles are spherical, (2) fillers are completely dispersed, and (3) the volume fraction of fillers is sufficiently small that the interaction among fillers may be neglected. The expression for the shear modulus of the composite μ**, which is derived here, is consistent with the viscosity of a suspension which has been derived by Oldroyd. Experiments who that the increase of Young's modulus by glass beads (GB) is lower in polystyrene (PS) than in epoxy resin (Ep). The reinforcement in Ep‐GB systems can be estimated by the well known formula derived assuming perfect adhesion. However, the reinforcement in PS‐GB systems is in rather good agreement with the formula derived here assuming interfacial slippage.

Elastic moduli of unidirectional and continuous carbon fiber reinforced plastics (CFRP) were analyzed theoretically, taking into account the anisotropic elastic property of the carbon fiber. This analysis is based upon the Eshelby's equivalent inclusion method12) and a kind of smearing-out method proposed by the authors.17) The solution procedure was formulated and specified, so that it could be easily applied to the stress analysis of the CFRP laminates. The procedure was applied to the investigation of the effective elastic moduli of unidirectional CFRP. And it was shown that the longitudinal Young's modulus ECL and Poisson's ratio vcTL (vcTL is the Poisson's ratio when tensile stress is applied in the longitudinal direction only) were almost proportional to the volume fraction of fibers (vf ), and the simple rule of mixture with respect to Ec and VcTL is available. The shear modulus GcTL depends only on GfTL , provided that the shear modulus of the matrix Gm= Em/2 (1 + vm) and of are constant. However GcTL is affected more seriously by the variation of Em than that of GfL Transverse Young's modulus EcT increases considerably with the increase of ET and decreases slightly with the increase of of VfTT VcTT increases with the increase of of T and increases slightly with the increase of EfT . The suffix c, f, m (of the symbols E, t . G) denote composite, fiber and matrix, respectively. Numerical results were also compared with the experimental data reported by Ishikawa et al.11) and the anisotropic elastic modulus of the carbon fiber TORAYCA T300 was estimated.

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This paper is concerned with the method of producing a novel silk/cotton composite yam with improved tensile properties. This "double-core" twin spun yam is made by inserting raw silk continuous filament core yams in both spun silk and cotton strands. The tensile and compression properties of a few other yams with different structures and the crease recovery properties of the fabrics are discussed.We have been studying the new composite yams in ment warp (50 denier136 filaments, density = 64 ends/ relation to spun silk fabrics in order to improve on the cm) in a plain weave. nature of spun silk yam and expand silk manufacturing [4,5,6,7,8,9,10). In our previous paper [9], we YARN PRODUCTION reported on the new composite core twin spun silk yarn made by combining two production methodsfilament core and twin spinning.To develop this system, we attempted to improve on the core twin spun silk yarn by using multiple core yams. Although former core twin spun yarns had only one core yam, this novel and effective core twin spun yam has two cores. We have named this the "doublecore" twin spun silk yarn. We have also produced a few other yams of the same material contents (spun silk/cotton/raw silk continuous filament) and examined the properties of the yams and fabrics. Materials and Methods YARNS AND FABRICSThe mean lengths of the staple fibers were 64 mm for spun silk and 26 mm for cotton. Two kinds of raw silk continuous filament yams were used for the core yam-2.3 tex (21 denier) and 4.7 tex (21 denier X 2200 turns/cm, Z). For comparison with the doublecore twin spun yams, we used a single-core twin spun yarn and a twin spun yam, which were made with a twisted raw silk core yarn of 7 tex (21 denier X 3200 tums/cm, Z) and without the core yam, rcspcctivcly. In all the yams, the nominal fiber content was 50% silk/50% cotton, the yam count was about 29.5 tex (20 Ne), and the twist factor was 27.8 (t~rns/cm)tex'~ (3 (tums/inch)Nc-lo).Using the experimental yarns as weft (density = 25 pickslcm), fabrics were woven with a polyester fila-The components for producing double-core twin spun yarn on a spun silk ring spinning frame are illustrated in Figure 1. The upper drafting elements are omitted for clarity. In the improved spun silk ring spinning frame, the roller gauges were as follows: (a) 225 mm between the front and back rollers, (b) 80 mm between the second and third rollers in the apron device, and (c) 35 mm betwcen the second and front rollers. Both spun silk and cotton rovings were kept separate (approximately 20 mm) by guides in the drafting zone. The continuous filament core yams passed through each tension control disk inserted directly behind the front roller in the drafted strands by means of core yam guides. In yam production, the tension for all the core yams was set at 78% of the elastic limit, and the core tensions used for the three kinds of raw silk continuous filament yams were 25, 36, and 62 gf.

Ethylenediamine, hexamethylenediamine, ortho-, meta-, para-phenylenediamines and 2, 2-diamino -4 , 4, 6, 6-tetraphenoxy-cyclo-triphosphazene were used as the curing agents of an epoxy resin. Mechanical properties of the cured epoxies were determined by the dynamic mechanical measurements and uniaxial tensile tests as a function of temperature. To increase the Young's modulus and the glass transition temperature of the epoxy resin, aromatic amines are more effective than aliphatic amines, and the amines with short distances between amino groups are also effective. The amino-phosphazene investigated in this paper is effective to increase the room temperature Young's modulus. However, it is not effective to increase the glass transition temperature of the epoxy resin, because of the steric hindrance during the curing reaction. The resistances of the epoxy resin to the immersion into water, HCl and NaOH aqueous solutions were also investigated.