Poly(ethylene methacrylic acid) (EMAA) has been used here as a thermally activated healing agent (HA) in three layered polyolefinic (3LPO) pipe coatings for the first time. The EMAA (HA) is blended with a linear low density polyethylene (LLDPE) modified with maleic anhydride (MAH) to create a healable multi-functional adhesive (HAMA), which is used to bind the fusion bonded epoxy primer and high density polyethylene topcoat layers together. Different compositions of the HA and modified adhesive were trialled for their healing efficiency using three different healing conditions to explore the effect of increasing temperature and applied load or force. The standard healing protocol used a healing temperature of 110 C and an applied load of 120 N for 60 min. A high temperature variant increased the temperature to 120 C while a high load variant increased the applied force to 240 N. Using a 1:1 HAMA adhesive, healing efficiencies of about 70% were achieved for the standard healing condition. Increasing the applied load to 240 N decreased healing to between 64% and 68% depending on the healing measurement, but at 120 C healing increased to between 82% and 84%. Regardless of the healing condition, overall healing efficiency increased with increasing EMAA (HA) concentration. This study also provided insight into the healing mechanism of the HAMA adhesives by highlighting some necessary features for healing. A bi-phasic microstructure consisting of large EMAA nodules with sufficient adhesion to the MAH-modified LLDPE was identified as being critical. Furthermore, increasing healing temperature increased healing efficiency due to the enhanced flow of EMAA and increased mobility of the polyethylene. Although these results are preliminary in nature, they do provide significant promise that multifunctional HAMA adhesives can be applied as simple, effective and repeatable 3LPO self-healing pipe coatings.

此处，聚甲基丙烯酸乙烯酯（EMAA）首次在三层聚烯烃（3LPO）管涂层中用作热活化愈合剂（HA）。将EMAA（HA）与经马来酸酐（MAH）改性的线性低密度聚乙烯（LLDPE）混合以创建可修复的多功能粘合剂（HAMA），该粘合剂用于粘合熔融粘合的环氧底漆和高密度聚乙烯面漆在一起。使用三种不同的愈合条件对不同成分的HA和改性粘合剂的愈合效率进行了试验，以探索提高温度和施加载荷或施加力的效果。标准的治疗方案使用的治疗温度为110°C，施加的负荷为120 N，持续60分钟。高温变量将温度提高到120 C，而高负荷变量将施加的力增加到240N。使用1：1 HAMA粘合剂，在标准治愈条件下，治愈率约为70％。根据愈合情况，将施加的载荷增加到240 N会使愈合降低到64％至68％，但在120°C时，愈合增加至82％至84％。无论愈合状况如何，总体愈合效率都随着EMAA（HA）浓度的增加而增加。这项研究还通过强调一些必要的愈合功能，提供了对HAMA胶粘剂愈合机制的见解。由大的EMAA结节组成的双相微观结构对MAH修饰的LLDPE具有足够的附着力，被认为是至关重要的。此外，升高的愈合温度由于EMAA的流动增加和聚乙烯的流动性增加而提高了愈合效率。尽管这些结果本质上是初步的，但它们确实为多功能HAMA粘合剂可作为简单，有效和可重复的3LPO自修复管道涂料应用提供了重大希望。