聚酯纖維於製程烘烤溫度與張應力作用下抗張潛變行為

Process Temperatures and Tensile Sress Effects on the Creep Tensile Behavior of Polyester Yarns

焙富莊(Bei-Fu Chuang)

指導教授 ： 謝啟萬

國立屏東科技大學/工學院/土木工程系所/碩士(2011年)

https://doi.org/10.6346/NPUST.2011.00244

摘要

柔性地工格網係由聚酯纖維編織而成，在織製過程中，需高溫烘烤使其包覆材凝固，為防止高溫烘烤下之聚酯紗線收縮，在生產過程中將施以張力。織製過程之烘烤時間與張力大小均可能影響聚酯纖維紗線的抗張及潛變行為，須加以探討以評估織造後格網的行為影響。
在烘烤溫度與張力作用後，經烘烤溫度（150℃～170℃）越高聚酯纖維長度收縮量越多，丹尼數也越高，說明烘烤溫度差異對於材料有其一定影響性；而隨著張力提高，烘烤溫度對於試樣在長度與丹尼數上，無明顯差異性，故張力對於試樣之影響相較烘烤溫度之影響來的明顯；在張力介於5 %UTS～7.5 %UTS時，方可排除紗線長度收縮與丹尼數改變之狀況。
在傳統潛變試驗中，潛曲線斜率Type-A介於0.0941~0.1017 %/log(t, H)、Type-B介於0.0895~0.1327 %/log(t, H)及Type-C介於0.0499~0.0577 %/log(t, H)；潛變率中，經烘烤溫度與張力作用，各個聚酯紗線的曲線趨勢有良好的重複性，說明經烘烤溫度與張力作用後無明顯影響潛變試驗結果。加速潛變試驗結果中，參考時間（t-t’）為3000秒之分析結果，所推估之主曲線最為平滑，且與傳統潛變試驗曲線，有良好的相似故加速潛變試驗法有其一定適用性。
掃描式電子顯微鏡觀察下，經過烘烤溫度與張力作用後試樣之表面有產生較多之粗糙顆粒，而對於試樣本身並無明顯損傷；再經由1000小時傳統潛變試驗後，試樣表面出現凹陷與裂痕，故可以確定長期張力下，導致材料有明顯損傷之情形。

關鍵字

聚酯纖維 ； 傳統潛變試驗 ； 加速潛變試驗 ； 電子顯微鏡（SEM）

並列摘要

The objective of the study is to investigate the effects of stressing and heating procedures during geogrid manufacture process on the tensile and creep behavior of polyester yarns. Three types of polyester yarns were used in the study. The nominal unit weight of the polyester yarns were 2000, 1500, and 2000 deniers for Type A, Type B, and Type C products, respectively. The test yarns were also treated under heating temperatures of 150C and 170C, and stressing at various loadings. After the heating and stressing process, the treated yarns were also evaluated their tensile strength and creep behavior according to ASTM D2256, ASTM D5262, and ASTM D6992 test methods.
The polyester yarn shrinkage was observed under the heating process, higher heating process would induce higher shrinkage strain. A minimum of 5% UTS ~ 7.5% UTS prestressing load could be applied to eliminate the shrinkage strain. However, when the prestressing load increased up to 10% UTS, the stress strain tensile test curve changed from an S-Type curve to a near initial straight line failure curve.
The initial creep strain of the convention long term creep tests for the treated products decreased as increasing pre-stressing loads and showed good repeatability. The creep strain rates were 0.0941~0.1017 %/log (t, H), 0.0895~0.1327 %/log (t, H), and 0.0499~0.0577 %/log (t, H) for Types A, B, and Type C polyester yarns, respectively. The creep strain rates also decreased as increasing the treated temperatures. The accelerated creep test (SIM) results indicated that the analyzed master creep curves using reference lag time (t-t’) of 3000 s would fit the best with that obtained from associated conventional creep tests.
SEM test results indicated that no significant difference between the non-treated and treated samples before the creep test. However, a few dent spots and uneven waving surface areas on the scanning pictures of the treated samples after 1000 hours of conventional creep test were observed. The effects of the treated process and long term tensile load on the engineering behavior of polyester yarn need further investigation.

並列關鍵字

Polyester yarn ； Conventional creep ； stepped isothermal method ； SEM

參考文獻

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