A model for plasma modification of polypropylene using atmospheric pressure discharges

Abstract

Atmospheric pressure plasmas are commonly used to improve the wetting and adhesion properties of polymers. In spite of their use, the mechanisms for achieving these properties are unclear. In this regard, we report on a computational investigation of the gas phase and surface kinetics during humid-air corona treatment of polypropylene (PP) and the resulting modification of its surface properties while varying energy deposition, relative humidity (RH), web speed, and gas temperature. Using results from a global plasma chemistry model validated against experiments, we found that increasing energy deposition increased the densities of alcohol, carbonyl, acid, and peroxy radicals on the PP surface. In doing so, significant amounts of gas phase O 3 and N x O y are produced. Increasing the RH increased the production of peroxy and acid groups, while decreasing those of alcohol and carbonyl groups. Production of O 3 decreased while that of HNO 3 increased. Increasing the temperature decreased the concentrations of alcohol, carbonyl, and acid groups on PP while those of the peroxy radicals increased. For a given energy deposition, higher web speeds resulted in decreased concentrations of alcohols, peroxy radicals, carbonyl, and acid groups on PP.

H2generation in Ar/NH3microdischarges

“…The plug flow model used in this study, GlobalKIN, has been previously described in [10,11] and so will be only briefly discussed here. GlobalKIN is a volume averaged, global kinetics model for plasma chemistry which, in plug flow mode, resolves axial transport.…”

Surface characterization of plasma‐modified polyethylene by contact angle experiments and ATR‐FTIR spectroscopy

“…As a result, PE surface modification is usually required to increase the overall surface free energy above that of these classes of adhesives and inks, thereby enabling bonding and printing. [3] An increase in surface free energy can be obtained using wet chemical processes; however, ecological requirements force the industry to search for alternative environmentally friendly methods. [4] Recently, plasma treatment of polymers has been gaining popularity as a surface modification technique since it does not require the use of water and chemicals.…”

Tratamento de superfície de tubos de poliamida 11 com chama para deposição de revestimento hidrofílico biomédico

“…A Figura 2 apresenta um esquema simplificado do equipamento utilizado. consequentemente da área de contato, aumentando assim a energia livre de superfície [12] .…”

“…Tal tratamento provoca modificações químicas na superfície do material, induzindo a formação de grupos funcionais polares capazes de aumentar a interação entre os polímeros do substrato e do revestimento por meio de ligações secundárias [3] , melhorando a molhabilidade do substrato [10] e consequentemente a aderência da camada polimérica hidrofílica depositada [11] . A molhabilidade, que é a habilidade de um líquido de aderir em um sólido espalhando-se ao longo de sua superfície em diferentes graus, se relaciona diretamente com o grau de hidrofilicidade do material [12] . Esses tratamentos promovem também um aumento da rugosidade superficial, e Os aumentos realizados foram de 50, 500, 3000 e 5000 vezes, para cada tempo estabelecido.…”