再生PE地膜的生产技术

介绍了废旧PE薄膜或包装袋净化、造粒方法及其与新料共混生产地膜的工艺条件,所得再生PE地膜的指标符合国家标准。     

PE防雾膜卷取装置的改进

ＰＣ（聚乙烯）防雾膜是一种吹塑级薄膜，是由防雾母粒与低密度取乙烯按工艺配比混匀经ＰＥ－６５吹塑挤出机挤出吹塑而成。因防雾母粒具有的性能造成ＰＥ防雾膜表面异常光滑、导致生产中产生打滑现象，无法缠型。针对ＰＥ防雾膜生产过程中产生收卷打滑现象，进行了研究，并对卷取装置进行了改造。     

含β双键表面活性剂反应接枝聚乙烯的制备及性能

将合成的含β双键表面活性剂(βS)与辐照的线形低密度聚乙烯(PE-LLD)在双螺杆挤出机中进行反应接枝,并对接枝物的结构进行了表征。研究了单体含量、反应温度、转速对接枝率的影响,将接枝产物吹膜,对膜的流滴性能进行了表征,结果表明,PE-LLD接枝βS(PE-LLD-g-βS)的红外光谱在3446、1722和1123 cm~(-1)处有吸收峰,这是βS的羟基、酯基和醚键特征峰,说明βS已经接枝到PE-LLD分子链上；PE-LLD-g-βS的接枝率随单体含量的增加和反应温度的升高而增加,但随螺杆转速的提高而降低,当βS含量为2%(质量分数,下同)、反应接枝温度为200℃、螺杆转速为150 r/min时,接枝率为1．1%；60℃条件下,PE-LLD-g-βS膜的流滴期是76d,而普通流滴膜为17d。     

能减少PE膜熔体破裂的改进型滑石粉

滑石粉——一种常用的价廉的聚乙烯薄膜防粘连剂,最近开发出一些新的用途。这些新的用途包括减少氟碳弹性体聚合物加工助剂（ＰＰＡ）的用量和提高包装膜的防湿性能。滑石粉是一种有效的防粘连添加剂,但缺点是在聚烯烃膜生产中必需增加氟碳弹性体ＰＰＡ的添加量,以防止...     

高密度聚乙烯(HDPE)薄膜的光接枝改性

在氮气保护、紫外光照射下,以二苯甲酮为光引发剂,丙烯酸在ＨＤＰＥ薄膜表面的光接枝聚合改性。探讨了光照时间、单体浓度、单体种类、溶剂种类等反应条件对接枝效果的影响。用红外光谱、水接触角和染色程度表征接枝效果,水接触角由８０°降至３４．４°,染色程度增加约９９倍。结果表明,表面光接枝改性对薄膜本体的力学性能没有影响。     

两层（PP／PE PE／PE）共挤复合薄膜的试制

本厂于1985年从香港联毅机器制造厂引进了一套型号为LN-45的PP/PE共挤复合薄膜生产机组(包括两台主机)。经过三年来的消化吸收和生产使用,目前已能生产质量较好的共挤复合薄膜。现就将PP/PE和PE/PE复合薄膜的生产情况及产品性能作简要介绍。     

Graft copolymerization of polyethylene glycol methacrylate onto polyethylene film and its blood compatibility

In an attempt to produce surfaces that show low levels of adsorption of protein and adhesion of platelets, different molecular weights of polyethylene glycol methacrylate (PEG‐MA) were grafted onto polyethylene film by a preirradiation grafting process. The extent of grafting was found to be dependent on the storage condition of the irradiated polyethylene film, the preirradiated dose, reaction time and temperature, molecular weight of PEG‐MA, and the type of solvent. The grafting yield was found to decrease rapidly with storage time for irradiated polyethylene film stored at room temperature. On the other hand, the grafting yield in the irradiated polyethylene stored at −130°C remained nearly constant up to 20 days after irradiation. The grafting yield decreased with an increased PEG‐MA molecular weight. Human plasma protein was adsorbed onto control and PEG‐MA‐grafted polyethylene film surfaces, and the relative adsorbed amount of proteins on the surfaces was evaluated by electron spectroscopy for chemical analysis. The adsorbed protein and platelet adhesion on the polyethylene film surface decreased rapidly with the grafting yield. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 631–641, 1999     

Surface graft copolymerization of 2‐hydroxyethyl methacrylate onto low‐density polyethylene film through corona discharge in air

The corona discharge technique was explored as a means of forming chemically active sites on a low‐density polyethylene (LDPE) film surface. The active species thus prepared at atmospheric pressure in air was exploited to subsequently induce copolymerization of 2‐hydroxyethyl methacrylate (HEMA) onto LDPE film in aqueous solution. The results showed that with the corona discharge voltage, reaction temperature, and inhibitor concentration in the reaction solution the grafting degree increased to a maximum and then decreased. As the corona discharge time, reaction time, and HEMA concentration in the reaction solution increased, the grafting degree increased. With reaction conditions of a 5 vol % HEMA concentration, 50°C copolymerization temperature, and a 2.0‐h reaction time, the degree of grafting of the LDPE film reached a high value of 158.0 μg/cm² after treatment for 72 s with a 15‐kV voltage at 50 Hz. Some characteristic peaks of the grafted LDPE came into view at 1719 cm^?1 on attenuated total reflectance IR spectra (C?O in ester groups) and at 531 eV on electron spectroscopy for chemical analysis (ESCA) spectra (O_1s). The C_1s core level ESCA spectrum of HEMA‐grafted LDPE showed two strong peaks at ～286.6 eV (? C ? O? from hydroxyl groups and ester groups) and ～289.1 eV (O?C ? O? from ester groups), and the C atom ratio in the ? C? O? groups and O?C? O groups was 2:1. The hydrophilicity of the grafted LDPE film was remarkably improved compared to that of the ungrafted LDPE film. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2881–2887, 2001     

Ozone‐induced grafting of a sulfoammonium zwitterionic polymer onto low‐density polyethylene film for improving hemocompatibility

Ozone‐induced grafting was developed to improve the hemocompatibility of biomaterials based on low‐density polyethylene (LDPE). An LDPE film was activated with ozone and graft‐polymerized with N,N′‐dimethyl(methacryloylethyl)ammonium propane sulfonate (DMAPS). The existence of sulfobetaine structures on the grafted film was confirmed by X‐ray photoelectron spectroscopy and attenuated total reflection/Fourier transform infrared (ATR–FTIR). More DMAPS was grafted onto the LDPE film as the DMAPS concentration increased, as determined by ATR–FTIR. Static contact‐angle measurements indicated that the DMAPS‐grafted LDPE film had a significant increase in hydrophilicity. The blood compatibility of the grafted film was preliminarily evaluated with a platelet‐rich‐plasma (PRP) adhesion study. No platelet adhesion was observed on the grafted film incubated with PRP at 37°C for 180 min. This new sulfoammonium zwitterionic‐structure‐grafted biomaterial might have potential for biomedical applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3697–3703, 2006     

Peroxide‐initiated comonomer grafting of styrene and maleic anhydride onto polyethylene: Effect of polyethylene microstructure

Maleic anhydride has been grafted onto various polyethylenes (PEs) using 2,5‐dimethyl‐2,5‐(di‐t‐butylperoxy)hexane as a free radical initiator in the presence of styrene as a comonomer. Three polyethylenes, differing systematically in their levels of terminal unsaturation and branching, were selected to investigate the effect of these microstructural characteristics on the course of both grafting and crosslinking. It was observed that when polyethylenes containing high levels of terminal unsaturation were reacted in the presence of peroxide or peroxide–maleic anhydride, crosslinking events were enhanced. When styrene was added as comonomer to the reaction medium to eliminate these undesirable side reactions, crosslinking was still observed with those polyethylenes that contained a high concentration of terminal unsaturation. This is attributed to a low reactivity between styrene and the allylic radical generated on the polyethylene backbone, which is believed to be responsible for the increased crosslinking. However, in the presence of high concentrations of styrene, crosslinking was eliminated for PEs containing high degrees of branching. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 96–107, 2001     

Silane grafting reactions of low-density polyethylene

Reactions of vinyl trimethoxysilane grafting onto low-density polyethylene (LDPE) were investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. The silane grafting reactions were induced by a fixed amount of dicumyl peroxide at 0.2 part of reagent per hundred parts with respect to LDPE. Fourier transform infrared data demonstrated that the extent of the silane grafting reaction was increased as the amount of silane used, the reaction time, or the reaction temperature was increased. The apparent activation energy of the silane grafting reaction was 9.7 kJ mol⁻¹. Differential scanning calorimetry was used to follow the silane grafting reactions in situ at a heating rate of 20°C per minute. The silane grafting reaction was exothermic starting at about 150°C and ending at about 230°C, indicating a completion of the reaction in 4 min. The grafting reaction heat has linear relations to the amount of silane used. The grafting reaction heat of about 1 J/g of sample was generated during reaction per part of reagent per hundred parts of silane used. The reaction heat of silane grafting onto LDPE per mol of silane used was 14.5 kJ mol⁻¹ silane, and the reaction heat of peroxide that reacted with LDPE was −12 kJ mol⁻¹ peroxide. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 255–261, 1998     

Investigation of styrene‐assisted free‐radical grafting of glycidyl methacrylate onto high‐density polyethylene using response surface method

In this study, the free‐radical grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE) in the presence of styrene, as a comonomer, is investigated using a Brabender internal mixer. To optimize grafting level of GMA onto HDPE, response surface method (RSM) was exploited. Using RSM method of experimental design, it was possible to investigate the individual effects of various variables including dicumyl peroxide (DCP) concentration, GMA content, as well as reaction time, and their interactions on grafting efficiency. The fitted quadratic model obtained from statistical analysis is expressed by an approximating function to investigate the final torque as a responding variable over the experimental range of the independent variables. The grafting yield of GMA onto HDPE for the prepared samples was determined using titration/back‐titration technique and Fourier transform infrared spectroscopy (FTIR). According to the torque–time diagrams, increasing the DCP content led to an increase in GMA grafting yield. Also, it was found that the reaction time imparts minor effect on the final processing torque, and there exists an interaction between DCP and GMA content. The results of melt flow index (MFI) test showed that increasing the reaction time at constant DCP and GMA content enhances the MFI values of the samples, due to the more probability of chain scission phenomenon. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Melt free‐radical grafting of hindered phenol antioxidant onto polyethylene

A monomeric antioxidant (3) was prepared by reacting 3,5‐di‐tert‐butyl‐4‐hydroxybenzyl alcohol (1) with N‐[4‐(chlorocarbonyl) phenyl] maleimide (2). This reactive antioxidant was grafted onto polyethylene (PE) by melt processing with free‐radical initiators in a mini‐max molder. The IR spectra of the grafted PE showed that the monomeric antioxidant was introduced onto the PE. IR spectroscopic methods and titration were used for the quantitative determination of the extent of grafting of the monomeric antioxidant. Also, the extent of crosslinking was indicated by the gel content. Grafting occurred in the following order: dicumyl peroxide (DCP) > benzoyl peroxide > 2,2′‐azobisisobutyronitrile. The influences of the DCP concentration and monomeric antioxidant on the extent of grafting were studied. The effects of the reaction time and temperature were also determined. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2968–2973, 2000     

The grafting of methyl methacrylate onto ultrahigh molecular weight polyethylene fiber by plasma and UV treatment

In this study, ultrahigh molecular weight polyethylene (UHMWPE) fibers were treated with a gas plasma of argon for 5 min. The plasma-treated UHMWPE fibers were put into a methyl methacrylate solution with n-hexane or chloroform as the solvent and irradiated with a UV lamp. The UV irradiation time was changed. The surface topography that had a significant change on the fiber was seen by scanning electron microscopy. Infrared spectra (IR) and electron spectroscopy for chemical analysis (ESCA) were also studied to probe the surface atomic chemistry and to identify the functional groups and their relative changes with treatment conditions. The grafting content was estimated by the titration of esterfication method. It was found that the grafting amount for the system with chloroform as the solvent is larger than that for the system with n-hexane as the solvent. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:365–371, 1997     

Grafting of PEG400 onto the surface of LLDPE/SMA film

Linear low-density polyethylene (LLDPE) was melt and blended with styrene-maleic anhydride copolymer (SMA). The blending films were then immersed in poly(ethylene glycol)400 (PEG400) at room temperature. The surface composition of the blend films was determined by Fourier transform infra-red spectroscopy coupled with a variable incidence angle attenuated total reflection accessory (ATR-FTIR). Results show that PEG400 can be grafted onto the surface of the films via esterification with SMA. The immersion of PEG promotes the enrichment of SMA onto the surface of the films. The water contact angle data show that grafting of PEG400 onto PE can greatly improve the hydrophilicity of the PE surface. These experiments show that surface functionalization of polyethylene films by blending SMA and then surface grafting of PEG is feasible, which suggest an effective and simple route for PE surface modification via blending and grafting. Translated from Acta Polymerica Sinica, 2006, (6), 829–832 [译自: 高分子学报]     

Thermosensitive surface properties of polyethylene film with poly(N-isopropylacrylamide) chains prepared by corona discharge induced grafting

Polyethylene (PE) film was treated by corona discharge and then grafted with N-isopropylacrylamide (NIPAAm) for modification of the surface. The grafted amount was determined by gravimetry and the surface morphology was observed by using a scanning electron microscope. The surface analysis was carried out with a x-ray photoelectron spectroscopy and electron probe microanalysis. It was clarified that grafting was limited surface and there was no change of the surface morphology after grafting. The water absorption at various temperature under the absolute humidity (11.4 g/cm³) and the leakage of electrostatic charge from PE film were measured. PolyNIPAAm that was introduced onto PE surface has hydrophilic-hydrophobic transition properties at the 32°C in the atmospheric condition. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1773–1779, 1998