Effect of Low Molecular Weight Oxidized Materials and Nitrogen Groups on Adhesive Joints of Polypropylene Treated by a Cold Atmospheric Plasma Jet

Abstract

Polypropylene is a typical representative of synthetic polymers that, for many applications including adhesive joints, requires an increase in wettability and chemical surface reactivity. Plasma processing offers efficient methods for such surface modifications. A particular disadvantage of the plasma jets can be the small plasma area. Here, we present a cold atmospheric plasma radio-frequency slit jet developed with a width of 150 mm applied to polypropylene plasma treatment in Ar, Ar/O2 and Ar/N2 We identified two main parameters influencing the tensile strength of adhesive joints mediated by epoxy adhesive DP 190, nitrogen content, and the amount of low molecular weight oxidized materials (LMWOMs). Nitrogen functional groups promoted adhesion between epoxy adhesive DP 190 and the PP by taking part in the curing process. LMWOMs formed a weak boundary layer, inhibiting adhesion by inducing a cohesive failure of the joint. A trade off between these two parameters determined the optimized conditions at which the strength of the adhesive joint increased 4.5 times. Higher adhesion strength was previously observed when using a translational plasma gliding arc plasma jet with higher plasma gas temperatures, resulting in better cross linking of polymer chains caused by local PP melting.

A Method for the Immobilization of Chitosan onto Urinary Catheters

“…Such short treatment times are beneficial in terms of time-optimization of the treatment process because they cannot cause overtreatment or the formation of weakly bound layers of low-molecular-weight oxidized materials (LMWOM). LMWOM is detrimental to good adhesion [ 22 , 23 ], although it was reported in one case that LMWOM might even be incorporated into the adhesive, resulting in adhesion enhancement [ 24 ]. However, such a scenario is not very likely to occur.…”

“…If the catheter surface has little or no lubricity, this will result in microtrauma or tiny cuts in the urethral tissue. Urethral trauma can lead to hematuria (blood in the urine), pain, further infection, and/or discomfort [ 23 ]. Therefore, it is important to improve hydrophilicity of the catheters.…”

X-ray Ptychographic Imaging and Spectroscopic Studies of Plasma-Treated Plastic Films

“…These morphological changes may be due to the breakup and removal of the top layer of the polymer film caused by interaction with the reactive species generated by the plasma on the surface. Moreover, there are some bulges at the surface of PET in SEM images that could represent the low-molecular weight oxidizing products which were reported previously after plasma treatments of polymer films [38,39]. In the literature, several studies visualized the morphological changes of PET film after plasma treatments by atomic force microscopy (AFM) [40][41][42].…”

Investigation of the effect of atmospheric pressure plasma application on bond strength of POM and PP materials

“…Plazma işleminin, plastik yüzeylerinde polar gruplar oluşturarak zayıf yüzey özelliklerini iyileştirdiği yapılan araştırmalar sayesinde bilinmektedir [18][19][20][21]. Yüzey enerjisini iyileştirmesinin yanında yüzey pürüzlülüğünü artırarak temas yüzeyini iyileştirmekte, böylelikle boyama, kaplama, yapışma uygulamalarında da yapışma dayanımı yükselmektedir [5,22,23].…”