Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (...Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the展开更多
The aging effects of the contact angle and surface energy on polyethylene terephthalate (PET) have been investigated with surface modification by water vapor plasma. The experimental results show that the contact ang...The aging effects of the contact angle and surface energy on polyethylene terephthalate (PET) have been investigated with surface modification by water vapor plasma. The experimental results show that the contact angle of water and PET decreases obviously and surface energy increases. However, with the increase of the aging time, the contact angle and surface energy change back gradually to original state.展开更多
Polyethylene terephthalate(PET) resin was hydrolyzed to terephthalate acid(TPA) and ethylene glycol(EG) under microwave irradiation.The effects of crystallinity on the depolymerization of PET was investigated.PET resi...Polyethylene terephthalate(PET) resin was hydrolyzed to terephthalate acid(TPA) and ethylene glycol(EG) under microwave irradiation.The effects of crystallinity on the depolymerization of PET was investigated.PET resin was isothermal crystallized at temperature of 140,170,200 and 230 ℃ for 5 hours,the crystallinity of the resin was 25.7%,29.5%,33.9% and 40.6%,respectively,then the resin with different crystallinity was hydrolyzed under microwave irriadition. Under the same conditions of hydrolytic depolymerization, the degree of PET depolymerization decreased from 72.8% to 69.34% with the increase of crystallinity of PET resin,the rate of depolymerization varied little with the increasing of crystallinity of PET,this indicated that the crystallinity of PET has little effect on the hydrolytic depolymerization.The crystallinity of PET was increased during the temperature elevating process of the hydrolytic depolymerization.Investigation by DSC proved that the crystallinity of PET resin increased notability during the same temperature elevating process as the hydrolyzed depolymerization.According to the theory that depolymerization was firstly proceed in the amorphous phase,the crystallinity should increase during the reaction.However,the crystallinity of PET residue was decreased during all the reaction process,this indicates that the hydrolysis did not preferentially occur in the amorphous phase.展开更多
It was demonstrated that some level of order exists in glassy poly(ethylene terephthalate) by depolarized light intensity(DLI) technique, but this order is different from that in crystalline PET. The degree of order i...It was demonstrated that some level of order exists in glassy poly(ethylene terephthalate) by depolarized light intensity(DLI) technique, but this order is different from that in crystalline PET. The degree of order in glassy PET decrease with increasing temperature between 288-343 K. The active energy of this transition is about 22 56 kJ/mol. The IR analysis indicated that this order relates to gauche structure of the ethyleneglycol fragments. The decrease of order with temperature comes from the increase of distance between the order segments.展开更多
文摘Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the
文摘The aging effects of the contact angle and surface energy on polyethylene terephthalate (PET) have been investigated with surface modification by water vapor plasma. The experimental results show that the contact angle of water and PET decreases obviously and surface energy increases. However, with the increase of the aging time, the contact angle and surface energy change back gradually to original state.
文摘Polyethylene terephthalate(PET) resin was hydrolyzed to terephthalate acid(TPA) and ethylene glycol(EG) under microwave irradiation.The effects of crystallinity on the depolymerization of PET was investigated.PET resin was isothermal crystallized at temperature of 140,170,200 and 230 ℃ for 5 hours,the crystallinity of the resin was 25.7%,29.5%,33.9% and 40.6%,respectively,then the resin with different crystallinity was hydrolyzed under microwave irriadition. Under the same conditions of hydrolytic depolymerization, the degree of PET depolymerization decreased from 72.8% to 69.34% with the increase of crystallinity of PET resin,the rate of depolymerization varied little with the increasing of crystallinity of PET,this indicated that the crystallinity of PET has little effect on the hydrolytic depolymerization.The crystallinity of PET was increased during the temperature elevating process of the hydrolytic depolymerization.Investigation by DSC proved that the crystallinity of PET resin increased notability during the same temperature elevating process as the hydrolyzed depolymerization.According to the theory that depolymerization was firstly proceed in the amorphous phase,the crystallinity should increase during the reaction.However,the crystallinity of PET residue was decreased during all the reaction process,this indicates that the hydrolysis did not preferentially occur in the amorphous phase.
文摘It was demonstrated that some level of order exists in glassy poly(ethylene terephthalate) by depolarized light intensity(DLI) technique, but this order is different from that in crystalline PET. The degree of order in glassy PET decrease with increasing temperature between 288-343 K. The active energy of this transition is about 22 56 kJ/mol. The IR analysis indicated that this order relates to gauche structure of the ethyleneglycol fragments. The decrease of order with temperature comes from the increase of distance between the order segments.
