• Fibers and Polymers
• /
• 제7권4호
• /
• pp.432-435
• /
• 2006

High Modulus and high tenacity polypropylene fibers have been prepared by drawing on a gradient heater. Results show that fiber properties are significantly affected by temperature profiles of final stage drawing on a gradient heater. The gradient drawn filaments showed superior mechanical properties when compared to filaments drawn over a constant temperature heater. Fibers with initial modulus of 16.4 GPa and tenacity of 670 MPa have been manufactured in the process. The nature of the gradient drawing had a significant effect on end properties. The superior mechanical properties are attributed to the high crystal perfection and crystallinity and low void fractions obtained at high draw ratios when drawn over a gradient heater.

• Computers and Concrete
• /
• 제17권6호
• /
• pp.831-848
• /
• 2016

This study aims to characterize the multiple cracking behavior of HTPP-ECC (High tenacity polypropylene fiber reinforced engineered cementitious composites) by Digital Image Correlation (DIC) Method. Digital images have been captured from a dogbone shaped HTPP-ECC specimen exhibiting 3.1% tensile ductility under loading. Images analyzed by VIC-2D software and ${\varepsilon}_{xx}$ strain maps have been obtained. Crack widths were computed from the ${\varepsilon}_{xx}$ strain maps and crack width distributions were determined throughout the specimen. The strain values from real LVDTs were also compared with virtual LVDTs digitally attached on digital images. Results confirmed that it is possible to accurately monitor the initiation and propagation of any single crack or multiple cracks by DIC at the whole interval of testing. Although the analysis require some post-processing operations, DIC based crack analysis methodology can be used as a promising and versatile tool for quality control of HTPP-ECC and other strain hardening composites.

• 대한화학회지
• /
• 제23권6호
• /
• pp.412-416
• /
• 1979

폴리프로필렌纖維는 他纖維에 比하여 機械的, 化學的性質이 매우 優秀하나 難染性 때문에 衣料用으로는 別로 쓰여지지 않고 있다. 폴리프로필렌의 染色性을 向上시키기 爲한 많은 硏究와 特許가 나와있으나 이들 大部分은 纖維의 개질등에 의한 방법으로서, 纖維에 직접, 견고한 染色을 할 수 있는 染料의 硏究는 거의 없다. 著者들은 카르벤을 生成시키므로써 他 纖維에는 勿論 폴리프로필렌纖維에 直接 染色될 수 있는 새로운형의 反應性染料를 合成하였다. 卽 알데히드基를 가지는 分散染料와 토실히드라진으로부터 合成한 새로운 反應性染料로서 폴리프로필렌을 染色한 結果, 濃色의 堅固한 染色物을 얻을 수 있었다.

• Fibers and Polymers
• /
• 제5권1호
• /
• pp.59-67
• /
• 2004

The development of high tenacity, high modulus monofilaments from Polypropylene/Clay nanocomposite has been investigated. Pure sodium montmorillonite nanoclay was modified using hexadecyl trimethyl ammonium bromide (HTAB) via an ion exchange reaction. Pure and modified clay were characterized through X-ray diffraction, FTIR and TGA. The modified clay was melt blended with polypropylene (PP) in presence of a swelling agent. Composite filaments from PP/Clay nanocomposite were prepared at different weight percentages of nanoclay and the spinning and drawing conditions were optimized. The filaments were characterized for their mechanical, morphological and thermal properties. The composite PP filaments with modified clay showed improved tensile strength, modulus and reduced elongation at break. The composite filaments with unmodified clay did not show any improvement in tensile strength but the modulus improved. The sharp and narrow X-ray diffraction peaks of PP/nanoclay composite filaments indicate increase in crystallinity in presence of modified clay at small loadings (0.5 %). The improved thermal stability was observed in filaments with modified as well as unmodified clays.

• Fibers and Polymers
• /
• 제5권4호
• /
• pp.264-269
• /
• 2004

The present paper deals with improvement in disperse dyeablility as well as imparting of cationic dyeablility to difficultly dyeable polypropylene by a melt blending technique. Isotactic polypropylene (PP) was blended with fibre grade polybutylene terephthalate (PBT), cationic dyeable polyethylene terephthalate (CDPET) and polystyrene (PS), individually. The resulting binary blends were spun and drawn into fibres at draw ratio 2, 2.5, and 3. The compatibility of blends, structural changes of fibres in terms of X-ray crystallinity, relative crystallinity, sonic modulus, birefringence and thermal stability were examined. The blended fibres were found to be disperse dyeable by the conventional method of high temperature and high pressure dyeing. And this dye ability increased with increase in the level of substitution. PP/CDPET blend also exhibited dyeablility with cationic dyes in addition to that with disperse dyes. The optimum level of blending was predicted keeping in view of tenacity and thermal stability of melt blend fibres. The wash fastness properties of the dyed fibres were found to be of high rate.