The A-B-A block copolymers were prepared by the ring opening polymerization of L-lactide by the polypropylene glycol (PPG; Mw/Mn=1.1, Mn=4000) with $Me_3Al-H_2O$ as the catalyst. When the feed ratios of PPG were over 5 and 10 wt% relative to L-lactide, the polymerization of L-lactide took place from the PPG hydroxyl terminals to give the desired A-B-A block copolymers in high yields. The resulting molecular weights were in good agreement with the values estimated from the monomer conversions and the feed ratios of PPG. At the lower feed ratios of PPG, the poly(L-lactic acid) (PLLA) homopolymer was formed along with the block copolymers. The block copolymers were melt-spun by the conventional method and the fibers obtained were extended by drawing at $60^{\circ}C$. At the same draw ratio, the modulus of the fibers was decreased with increasing PPG content in the block copolymers. The fibers of the PLLA-PPG-PLLA block copolymers with different contents of PPG were subjected to degradation in vitro. Upon immersion in a phosphate buffer solution (pH=7.4), the fibers showed a time-dependent decrease in tensile strength with accompanying surface erosion. The degradation rate of this fiber was much higher than that of PLLA fiber. It was therefore suggested that the block copolymers comprising PLLA and PPG, have high potential as the biodegradable suture with improved flexibility and biodegradability.

Linen fabrics were treated with 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) by pad-dry-cure process to give the wash and wear properties. The effects of curing temperatures, concentration of crosslinking agent and catalyst on the wrinkle recovery of the fabrics were investigated. The additives, triethanol amine(TEA) and/or poly(ethylene glycol)(PEG), were used to overcome the serious reduction of the strength of treated fabrics. The mixed additive, TEA/PEG/urethane resin, was added to the padding bath to improve the strength retention of treated fabrics. The fabrics treated with DMDHEU/TEA or DMDHEU/PEG had better strength retention than those of the fabrics treated with DMDHEU only. The fabrics treated with DMDHEU/TEA/PEG had the same degree of wash and wear properties as those of the fabrics treated with DMDHEU only, but better strength retention than those of the fabrics treated with either DMDHEU/TEA or DMDHEU/PEG. The addition of urethane resin to the padding liquor of DMDHEU/TEA/PEG improved the strength retention of treated fabrics further more.

Wool fiber was treated with PPE (polyglycerol polyglycidyl ether) multifunctlonal epoxide compound, in order to introduce crosslinks onto the fiber. The optimum conditions, such as NaSCN concentration, time and temperature, were determined in the reaction of wool fiber with PPE epoxide. The amount of epoxide added onto wool fiber increased linearly with the epoxide concentration in the reaction media. The solubility, degree of swelling and tensile properties were significantly affected as the add-on(%) of PPE epoxide varied. These properties indirectly confirmed that the crosslinks were introduced inside the fiber. The direct evidence for the crosslinkins formation was also obtained from the decrease in the cystine content. SEM and X-ray diffraction analysis suggest that the deposition of grafted epoxide copolymers occurs on the surface of wool fiber, particularly in the case of high epoxide add-on(%).

The structural characteristics and mechanical properties such as tensile, bending, compression and surface of the silk fabrics manufactured by the different shrinkage of filling varns were investigated. For this study, the filling yarn was treated with the salt solution to make shrinkage and. the results obtained are as follows; ① In fabric structure, high shrinkage fabrics have more thickened and bulkier feature with the reduced linearity and yarn integrity than low shrinkage fabric. ② As the filling shrinkage of the fabrics increased, tensile strength decreased, while bending rigidity, compressional energy and bending hysteresis increased. ③ Surface characteristics such as friction coefficient and thickness variation of highly shrinkage fabrics became relatively roughened state. ④ Since stiffened and roughened characteristics of highly shrinkage fabrics, drapabilities of them were significantly lowered. Additionally thermal insulation property of high shrinkage fabric was higher than that of low shrinkage fabric due to bulky and thickened feature. From the results, it is considered that the silk fabrics with high filling shrinkage have the good bulkiness and heat keeping properties and thus they have the suitable characteristics for high quality men's and women's formal gaments.

The buckling optimization of square rod composites with a given geometry subjected to uniaxial compression has been studied in terms of fiber volume fraction and thickness factor in the gradient structures by using a sequential linear Programming method. Discrete gradient structures in the designing of composites have shown some advantage of weight reduction in the design of composite structures with equivalent performance. Gradient structures have shown 12~18% reduction in gross fiber volume and 8-12% in weight compared to the uniform conventional homogeneous structures.

Thermal behaviour of polyglycolic acid in melt polymerization of glycolide was investigated as a function of lauryl alcohol content. There were showed three endothermic peaks such as glycolide melting peak, lower molecular weight melting (oligomer) peak and higher molecular weight melting peak at early stage on glycolide melt polymerization under lauryl alcohol. But there were showed only two peaks, glycoside melting peak and lower molecular weight melting peak without laurel alcohol. Conversion increased slowly with the reaction time up to 50 minutes, and then gave a sudden increase above that. The reaction time to disappear in glycolide melting peak during polymerization was shortened with the increase of lauryl alcohol content. Zero-shear viscosity of polyglycolic acid decreased with the increase of free acid content in glycolide.

Quarternary polymers (EBVM) were synthesized by polymerization of 2-ethylhexyl acrylate, butyl acrylate, vinyl acetate, and maleic anhydride. Solution type acrylic pressure-sen-sitive adhesives (PSA's) of melamine derivative (EBVMM) were prepared by crosslinking of EBVM with butoxymethyl melamine. The adhesion properties of EBVMM were evaluated using polyester films coated with this PSA's. EBVMM-2 showed peel adhesion of 900 g/inch width, shear adhesion of 1700 mins, and tackiness of 14/32. It has been proved that the acrylic PSA's developed in this study can be used as a permanent PSA's.

Nylon 6 film (IAF film) and powder were iodinated with 0.2, 0.4, 0.6 and 1.0 N of I$_2$/KI aqueous solutions, and the iodinated powder was used to make the films iodinated before forming (IBF film). The crystal structure and drawability of the two kinds of films were investigated through X-ray diffraction, DSC, IR analysis, and tensile test. In the case of IAF films, not only the 4 steps in formation of the nylon 6-iodine complex crystal with increasing concentration of I$_2$/KI but also the existence of $I^-_5$ ions over the 2nd step were confirmed again by X-ray diffraction and DSC analysis. In the case of IBF films, however, the formation of the complex crystal was not confirmed. but the formation of new $\alpha$- and ${\gamma}$-crystals of nylon 6 was confirmed by X-ray diffraction, IR, and DSC analysis. The tensile behavior of IAF showed the much lower yield and breaking loads and the much higher breaking elongation in comparison with untreated film, but the elongation of IBF films was lower though the load was lower than that of IAF films. The maximum draw ratio and initial modulus were 3.5 and 0.88 GPa for the untreated film, 9.5 and 9.48 GPa for the drawn IAF films after removal of iodine, and 5.5 and 1.16 GPa for the drawn IBF films after removal of iodine. The maximum values of draw ratio and initial modulus could be achieved from the films iodinated with 1.0 N I$_2$/KI solution, and at drawing temperatures of 4$0^{\circ}C$ and 60% for IAF and IBF films, respectively.

By use of thermal bonding method, 2-phase geotextile composed of bonded and nonbonded parts for reinforcement was made from a needle punched polypropylene nonwoven to analyze the viscoelastic behaviors. The yield strain of 2-phase geotextiles is lower than that of simply needle punched geotextile and this is due to the increase of stiffness by uniform distributions of bonded parts. The interpretation of stress relaxation behaviors of 2-phase gootextile was based on Schapery's theory. The equilibrium state of stress relaxations approached to 10 sec independent of additional strains, and relaxation times existed within the range of 10 sec. The strain function, h(e), was divided into elastic and plastic regions and the transition between these regions occurred at 15∼25% strain ranges. Finally, the relaxation behavior of bonded parts was governed by (∞) and the behavior of unbonded parts was governed by (0)- (∞).