Khalili Gashtroudkhani Ali, Dahmardeh Ghaleno Mohammad, Soltan Abadi Saeed, Pouyani Maryam
Faculty of Polymer Processing, Iran Polymer and Petrochemical Institute, Tehran, Iran.
Department of Wood and Paper Sciences and Technology, University of Zabol, Zabol, Iran.
Front Chem. 2025 Mar 19;13:1545984. doi: 10.3389/fchem.2025.1545984. eCollection 2025.
Polymeric shock tubes are now widely used in explosives systems for drilling and mining operations. Most shock tubes on the market consist of three layers of polymer, the first layer being Surlyn 8940 copolymer, the second layer Nucrel 31001 and the outer layer Borostar ME 6053 medium density polyethylene. Surlyn and Nucrel are usually sourced from DuPont, polyethylene from Charlotte Boralis. the main goal in this research is reducing the price of final shock tube and reuse the waste tube of plant (rejected shock tube) with improving the properties of product. For reaching to this goal, using polyethylene blend with available raw materials in the country and mixing them with rework from the shock tube production plant. For this purpose, different proportions of low- and high-Density polyethylene are blend using a twin-screw extruder and finally mixed with some of the factory's polymer rework. In the first phase, the low-density polyethylene LDPE 020, the high-density polyethylene HDPE HI 0500 and the filler calcium carbonate were blend in a twin-screw extruder and compounded with different percentages of 20/75/5, 30/65/5, 40/55/5 and 47/47/6 percent respectively. In the second phase, the resulting blend was mixed physically with 5, 10 and 15 percent three-layer tube rework (which was crushed with a crusher or pelletizer). The results showed that the 47/47/6 percent mixture had the best composition in terms of the production process, the properties of blend in terms of tensile strength (17/3 MPa), elongation percentage (458%) was suitable. In order to reduce the waste and cost of the product, the best processing results, product properties and costs are obtained when the above composition is mixed with crushed shock tube rework in a ratio of 90/10 (blend/rework). Tensile strength at break was 20/01 MPa and elongation at break was 478%. After evaluating the raw materials and accepting the results, the polymer blends were used on an industrial scale to produce shock tubes. The performance of the resulting shock tubes was then compared using various tests, including mechanical tests, oil penetration resistance, thermal shrinkage (in 60°C: upper 7% and in 80°C: upper 9%), burst strength, thermal aging (before aging:170 N, after aging: N, N, N, N: upper 170 N), and explosion velocity (upper 1890 m/s). The results showed that by using the polymer blend with rework, the mechanical properties of the shock tubes produced met the standard (tensile strength of more than 170 N/m and elongation percentage of more than 220). The results of the oil penetration resistance (45-50 h), burst strength and aging tests also showed that all shock tubes manufactured with the new third layer had acceptable properties and were on the same level as shock tubes made of Boralis polyethylene.
聚合物激波管目前广泛应用于钻探和采矿作业的炸药系统中。市面上的大多数激波管由三层聚合物组成，第一层是苏丽龙8940共聚物，第二层是纽曲尔31001，外层是博罗斯塔ME 6053中密度聚乙烯。苏丽龙和纽曲尔通常来自杜邦公司，聚乙烯来自夏洛特博雷利斯公司。本研究的主要目标是降低最终激波管的价格，并在提高产品性能的同时对工厂的废管（不合格激波管）进行再利用。为实现这一目标，将聚乙烯与国内现有的原材料混合，并与激波管生产厂的返工料混合。为此，使用双螺杆挤出机将不同比例的低密度和高密度聚乙烯进行混合，最后与工厂的一些聚合物返工料混合。在第一阶段，将低密度聚乙烯LDPE 020、高密度聚乙烯HDPE HI 0500和填料碳酸钙在双螺杆挤出机中混合，并分别以20/75/5、30/65/5、40/55/5和47/47/6%的不同百分比进行混配。在第二阶段，将所得混合物与5%、10%和15%的三层管返工料（用破碎机或造粒机粉碎）进行物理混合。结果表明，就生产工艺而言，47/47/6%的混合物具有最佳组成，其拉伸强度（17/3 MPa）和伸长率（458%）的混合性能较为合适。为了减少产品的浪费和成本，当上述组合物与粉碎的激波管返工料按90/10（混合物/返工料）的比例混合时，可获得最佳的加工效果、产品性能和成本。断裂拉伸强度为20/01 MPa，断裂伸长率为478%。在对原材料进行评估并接受结果后，聚合物共混物被用于工业规模生产激波管。然后使用各种测试对所得激波管的性能进行比较，包括机械测试、耐油渗透性、热收缩率（在60°C时：最高7%，在80°C时：最高9%）、爆破强度、热老化（老化前：170 N，老化后：N、N、N、N：最高170 N）和爆炸速度（最高1890 m/s）。结果表明，通过使用聚合物共混物和返工料，生产的激波管的机械性能符合标准（拉伸强度超过170 N/m，伸长率超过220）。耐油渗透性（45 - 50小时）、爆破强度和老化测试的结果还表明，所有用新的第三层制造的激波管都具有可接受的性能，与由博雷利斯聚乙烯制成的激波管处于同一水平。
