The conductive behavior and structural characteristics in the I+-beam-implanted layer of plasma-polymerized pyrrole film

A dense organic film was prepared by plasma polymerization of pyrrole. A 20 keV I⁺ implantation at a fluence of 1 × 10¹⁶ ions cm⁻² was used to produce a conducting surface layer due to doping. The characteristics of the implanted layer have been investigated using ion beam analysis techniques, X-ray photoelectron spectroscopy, and near-infrared to ultraviolet spectroscopy. The charge carriers transport in this implanted layer was also analyzed in the temperature region of 120 to 297 K. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 1743–1751, 1998     

Tailoring terpenoid plasma polymer properties by controlling the substrate temperature during PECVD

Polymers derived from natural, minimally‐processed materials have recently emerged as a more sustainable alternative to synthetic polymers, with promising applications in biocompatible and biodegradable devices. Plasma‐enhanced deposition is well‐suited to one‐step, fast, and efficient synthesis of highly crosslinked inert polymers directly from natural resources, however, fabrication of biologically active polymers remains a challenge. Plasma processing parameters influence the properties such as surface energy, roughness, morphology, and chemical composition of deposited polymers and thus their final applications. This article reports on the important role of substrate temperature (T_S) in the chemical composition, wettability, refractive index, and crosslinking density of plasma polymers derived from terpenoids. Experiments are conducted as a function of deposition power P_d, and substrate temperature, T_S. T_S varied from 40 to 280 °C and is externally controlled. Atomic force microscopy analysis reveals the change in deposition mechanism attributed to shadowing effect at higher T_S and P_d. Increase in band gap (E_g) with high T_s deposition for terpenoid based plasma polymers is observed. Swelling behavior analyzed by in situ ellipsometry affirms the enhanced crosslink density with increasing deposition rate. Fourier transform infrared analysis exhibits the formation of additional chemical moieties with increasing T_S. Increase in deposition rate with increasing T_S at higher P_d supports the theory of direct incorporation of depositing particles as dominant mechanism of plasma polymerization in this study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45771.     

Near perfect thin film flexible broadband optical absorber with high thermal/electrical conductivity

Flexible ultra-black absorber with high thermal/electrical conductivity finds huge applications in the field of stray light attenuation, solar collectors, flexible electronics, and electronic thermal management systems. In this work, we report the fabrication of ultrablack absorber consists of vertically aligned carbon nanotubes (VACNT) in Polydimethylsiloxane (PDMS) having an absorption capacity of more than 98% in UV–Vis wavelength and more than 94% in NIR wavelength range. It is observed that the PDMS-VACNT composite shows ultra-high absorption capacity due to enhanced impedance matching and multiple scattering. In addition to this, the PDMS-VACNT composite shows an emissivity of 0.94 along with a 118% increase in thermal conductivity. Moreover, with the infiltration of VACNT in PDMS, the sheet resistance decrease drastically to 0.08 KΩ/sq, which signify the possible use of ultrablack absorber in electronic skin and flexible sensors etc. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48855.     

Characteristics of nitrogen doped diamond-like carbon thin films grown by microwave surface-wave plasma CVD

Nitrogen doped diamond-like carbon (DLC:N) thin films were deposited on p-type silicon (p-Si) and quartz substrates by microwave (MW) surface-wave plasma (SWP) chemical vapor deposition (CVD) at low temperature (< 100 °C). For films deposition, argon (Ar: 200 sccm), acetylene (C₂H₂:10 sccm) and nitrogen (N: 5 sccm) were used as carrier, source and doping gases respectively. DLC:N thin films were deposited at 1000 W microwave power where as gas composition pressures were ranged from 110 Pa to 50 Pa. Analytical methods such as X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, FTIR and Raman spectroscopy were employed to investigate the chemical, optical and structural properties of the DLC:N films respectively. The lowest optical gap of the film was found to be 1.6 eV at 50 Pa gas composition pressure.     

Optical and thermal properties of commercial polymer film,modeling the albedo effect

Greenhouse cladding materials are an important part of greenhouse design. The cladding material controls the light transmission and distribution over the plants within the greenhouse, thereby exerting a major influence on the overall yield. Greenhouse claddings are typically translucent materials offering more diffusive transmission than reflection; however, the reflective properties of the films offer a potential route to increasing the surface albedo of the local environment. We model thermal properties by modeling the films based on their optical transmissions and reflections. We can use this data to estimate their albedo and determine the amount of short wave radiation that will be transmitted/reflected/blocked by the materials and how it can influence the local environment.     

Nanomechanical study of polymer‐polymer thin film interface under applied service conditions

Single layer and multilayer polymer thin film coating on polymer substrate are gaining significant importance in different industries. The quantitative and qualitative estimation of interface response for thin film coating under different service conditions is significantly important from the perspective of modeling and designing novel materials. However, to characterize an interface between the soft polymer layer and soft polymer substrate is challenging because of the confinement effect, surface roughness, the viscoelastic nature of the polymers involved, and most importantly, the comparable mechanical properties of soft polymeric film and polymer substrate. Nanoindentation technique was applied in this work to find out the mechanical response of thin film PMMA (100–200 nm) and Epoxy interfaces of different interfacial strengths. Interfaces of different strengths were obtained by exposing the film‐substrate system to different service conditions. It has been observed from this study that pile‐up plays a major role in finding out the mechanical response of the interfaces of different strengths. The hardness was observed to increase as the interfacial strength reduces. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43532.     

Preparation and characteristics of thin film with wear-resistant behavior on HDPE surface polymerized by C2H2–H2–SiH4 plasma

Plasma-polymerized deposition of an acetylene–hydrogen–silane mixture (C₂H₂–H₂–SiH₄) to obtain thin film with good wear behavior on a high-density polyethylene (HDPE) surface was present in this work. It was found that the bond between thin film and HDPE substrate was excellent and H₂ gas in system led the deposited thin film to better adhesive properties, but slower thin film deposition rate. Surface wear-resistant properties of modified HDPE were improved with the input of SiH₄. Infrared and X-ray photoelectron spectroscopy spectra suggested that there be large quantities of >CO, O H, C Si, and Si O groups in thin film and that the ratio of C to Si was increased due to the addition of SiH₄ and H₂, which inferred that the thin film structure and components lie between organic and inorganic materials. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1561–1566, 1998     

Adhesion of vacuum-deposited thin cobalt metal film to poly(ethylene terephthalate) pretreated with RF plasma

Specific polar groups were introduced on a poly(ethylene terephthalate) (PET) film surface by radio-frequency (RF) plasma treatment. These polar groups were analyzed quantitatively by ESCA, and their effect on the adhesion strength of vacuum-deposited thin cobalt metal film on the plasma-treated PET film surface was investigated. Hydroperoxide and hydroxyl groups introduced onto the PET film surface by RF plasma under an argon or oxygen atmosphere greatly increased the adhesion strength. In particular, oxygen plasma treatment at high RF power was most effective. A large number of amino groups were introduced by the ammonia plasma treatment, but they did not increase the adhesion strength.     

苇浆回用性能的研究

本文研究了漂白硫酸盐苇浆在反复回用过程中物理化学性能的变化规律。试验表明，随着回用次数增加，聚戊糖含量、保水值、纸页紧度、抗张与耐破强度、耐折度逐渐降低，且对原浆打浆有较大的下降趋势；平均聚会度、相对结晶指数与散射系数具有增加的总趋势；纤维平均长度由于细小级分流失有所增加；零距裂断长变化较小。打过浆与未打浆苇浆在回用过程中抗张指数与紧度均成对数直线关系，其斜率分别为2．481和2.09。     

Y型分子筛的理化性能与催化裂化焦炭选择性的关系研究

催化裂化过程中,大部分反应发生在催化剂活性组分——分子筛上,焦炭也主要在分子筛上产生。因此,从催化裂化的产焦机理出发,研究了Y型分子筛的理化性能如分子筛的晶胞、Na2O含量、结晶度、酸性、孔分布以及改性元素与催化裂化焦炭选择性的关系。阐述了改善Y型分子筛焦炭选择性的措施。     

Synthesis and device performance of an oxygen‐interrupted bipolar polymer host with carbazole and triphenylphosphine oxide in the main chain

A novel bipolar polymer host PC10CzPO, carrying hole‐transporting carbazole and electron‐transporting triphenylphosphine oxide units in the oxygen‐interrupted main chain, was synthesized and characterized. In addition to its excellent thermal stability and miscibility with phosphors, PC10CzPO is also reported to have a triplet energy (E_T) as high as 2.83 eV due to oxygen‐interrupted π‐conjugation, ensuring that PC10CzPO can be used as a suitable host material. The PC10CzPO‐based phosphorescent devices were investigated and compared, while doping with typical blue phosphor {iridium(III)[bis(4,6‐difluorophenyl)pyridinato‐N, C2]picolinate, FIrpic)}, green phosphor {tris[2‐(p‐tolyl)pyridine]iridium(III), Ir(mppy)₃}, and red phosphor [bis(1‐phenyl‐isoquinoline‐C2,N)(acetylacetonato)iridium(III), Ir(piq)₂acac]. As a result, the FIrpic‐based blue devices showed better device performances than those of red and green devices, which was ascribed to more effective energy transfer. This indicates that the choice of proper host and dopant emitters to fabricate phosphorescent polymer light emitting diodes (PhPLED) is a simple and effective approach to optimize device performances. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44461.     

Effect of chlorination and fluorination of benzothiadiazole on the performance of polymer solar cells

In order to explore the effects of chlorine and fluorine on photophysical properties and the differences, in this work, we synthesized five new polymers, P1 – P5 , in which benzo[1,2-b:4,5-b]dithiophene as the electron donating and benzothiadiazole as electron withdrawing. Analysis of these five polymers showed that the introduction of Cl and F atoms can deeper the highest occupied molecular orbital of these polymers and enhance the absorption of light by the species, thereby improving V_oc and J_sc. Chlorination has a stronger ability to reduce energy levels and broaden the absorption spectrum compared to fluorination. Among them, P2 showed an efficiency of 4.08% with J_sc of 11.28 mA/cm², V_oc of 0.79 V, and fill factor (FF) of 0.45. Since chlorination is easier than fluorination in terms of synthesis, it is advantageous for practical applications. Therefore, we think that chlorination should not be ignored when designing high efficiency photovoltaic materials, especially when their fluorinated counterparts have proven to have good properties.     

Development of waste tire‐derived graphene reinforced polypropylene nanocomposites with controlled polymer grade,crystallization and mechanical characteristics via melt‐mixing

In the present work, single layer graphene nanoplatelets (GNPs) derived from waste tires by recycling and upcycling approaches were integrated in homopolymer (Homo‐) and copolymer (Copo‐) polypropylene (PP) matrices by fast and efficient mixing in the melt phase. The effect of GNP content on crystallization and mechanical behaviors was investigated in detail at different loading levels. Regarding isothermal and non‐isothermal crystallization experiments, GNPs significantly accelerated the nucleation and growth of crystallites, and the crystallization degree in Homo‐PP nanocomposites was slightly higher than that of Copo‐PP based nanocomposites. Also, there was significant improvement in mechanical and thermal properties of GNP reinforced polymers compared to neat polymers. As the GNP concentration increased from 1 to 5 wt%, there was a gradual increase in flexural modulus and strength values. In tensile tests, an increase in GNP content in both polymer grades led to a slight increase in yield strength coming from the proper distribution of nano‐reinforcement by creating stress concentration sites. After the yield point, Homo‐PP based nanocomposites showed higher strain hardening than GNP reinforced Copo‐PP owing to a high crystallization degree and linear chains of Homo‐PP. This work showed that functionalized graphene can act as both nucleating and reinforcing agent in the compounding process and its exfoliation through polymer chains is much better in homopolymers at a faster and high shear rate. © 2020 Society of Chemical Industry     

Preparation and performance study of functional polymer with self demulsifying

In polymer flooding, the residual polymer in the produced fluid can increase the stability of crude oil emulsion, thereby negatively affecting the demulsification process. Therefore, a polymer that has no effect on the stability of crude oil emulsion is required. Herein, a polymerizable monomer with a demulsification function (MD) was synthesized and then copolymerized with acrylamide, acrylic acid, and 2-acrylamide-2-methylpropane sulfonic acid to prepare a novel copolymer (self-demulsifying polymer, PDM). The dissolution time, solution viscosity, shear resistance, static adsorption on quartz sand, and the effect on the crude oil emulsion stability of PDM were compared with those of regular polyacrylamide (PAM). Experimental results showed that owing to the steric hindrance effect of MD, the molecular weight of PDM was lower than that of PAM. Both polymers exhibited satisfactory solubility, solution viscosity, shear resistance, and static adsorption, which can meet the requirements of polymer for use in oil displacement. However, in contrast to PAM, PDM had no negative effect on the crude oil emulsion stability. This study provides a new solution to the problem of increased crude oil emulsion stability in polymer flooding.     

Additive and free-volume effects on the refractive index of a thiol-ene polymer network

A series of hard, transparent, thermoset polymer samples containing tetravinylsilane (TVS) and 1,3-benzenedithiol (BDT) with varying loadings of zirconium oxide clusters Zr₆(OH)₄O₄(OMc)₁₂ (ZOC) were synthesized. Resulting polymers exhibited a higher refractive index (n) than the parent polymer containing only the monomers TVS and BDT. The refractive index reached a maximum value of 1.711 at a ZOC loading of 3 wt% and then decreased as the ZOC concentration in the polymer matrix increased. The refractive index of ZOC was determined to be 1.540 using the Becke line method. Because the refractive index of ZOC is lower than that of the TVS–BDT polymer matrix, the finding that the incorporation of small quantities of ZOC can increase the refractive index of the TVS–BDT polymer composite was unexpected and is accounted for by the effects of ZOC on the packing efficiency of the composite.     

一种提高聚合物挤出流量在线测量精度的方法

针对聚合物挤出加工过程挤出流量间接测量的特点,提出了介于静态数字滤波与动态数字滤波之间的"转静态"数字滤波方法,将具有动态测量特点的直接测量变量转化为相对稳定的具有静态测量特点的间接测量变量。在此基础上,将限幅滤波和递推平均滤波应用于挤出流量在线测量的数据处理,以克服挤出过程中随机干扰和周期干扰对挤出流量测量精度的影响。通过实验选取最佳的滤波参数——滤波采样周期T及递推平均次数N,结果证明,"转静态"数字滤波输出值与挤出流量真值吻合度很好,符合对挤出流通量在线测量精度的要求。     

不同控释氮比例的控释氮掺混肥氮素淋失特征研究

采用模拟灌溉和模拟降雨方法,研究不同控释氮比例的控释氮掺混肥在原状土柱土壤中养分的淋失特征。研究结果表明,控释氮掺混肥显著降低了土壤中铵态氮、硝态氮的淋失,增强了土壤pH值缓冲性,提高了后期土壤溶液电导率;控释氮占59％的控释掺混肥具有“前控后保”的特点,适于推广应用。     

Effect of solvent quality on Poiseuille flow of polymer solutions in microchannels: A dissipative particle dynamics study

The Poiseuille flows of polymer solutions for varying quality solvents in microchannels have been simulated using dissipative particle dynamics. In particular, the velocity distributions and the polymer migration across the channel have been investigated for good, athermal, and poor solvents. The velocity profiles for all three kinds of solvent deviate from the parabolic profile, and the velocity profile of the athermal solvent falls in between the good solvent and the poor solvent. For the athermal solvent, a migration away from the wall due to the hydrodynamic interactions between the chains and the wall is observed, and a migration away from the channel center due to the different chain Brownian diffusivities is also observed. For the good solvent, because of the more stretched polymer chains, the migration away from the wall is stronger than that for the athermal solvent. However, the migration away from the channel center is not observed for good solvents. For the poor solvent, the hydrodynamic interaction within the chains is screened, and the polymer chains migrate toward the wall and appear to be absorbed by the wall. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47345.     

Fluorene‐based copolymers with donor–acceptor units on the side chain and main chain: Synthesis and application in polymer solar cells

Two narrow band gap fluorene‐based copolymers with donor–acceptor (D–A) structure on the polymer side chain and/or main chain are synthesized by Pd‐catalyzed Stille coupling reactions. The two copolymers have excellent thermal stability. The effects of D–A structure on the main and side chains on the absorption and electrochemical properties are studied. The copolymer PF‐BTh‐DBT with D–A structure both on the main and side chains has broader and stronger absorption and narrower band gap than the copolymer PF‐BTh with only a pendent D–A structure. The power conversion efficiency of the assembled solar cell using PF‐BTh‐DBT as donor and PC₇₁BM as acceptor is 1.6% with open‐circuit voltage (V_oc) 0.84 V under simulated AM 1.5 G solar irradiation (100 mW/cm²). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3276–3281, 2013     

A novel copolymer of methyl methacrylate with N-pentafluorophenyl maleimide: High glass transition temperature and highly transparent polymer

N-pentafluorophenyl maleimide (PFPMI) was synthesized. The homo and copolymers of PFPMI with methyl methacrylate (MMA) were prepared. The monomer reactivity ratio, r₁ (PFPMI) and r₂ (MMA) were 0.389 and 1.06 respectively. Q and e values for PFPMI were calculated as 1.00 and 1.30. The refractive indexes of poly(PFPMI) and PMMA were found to be similar; 1.4989 and 1.4953 at 532 nm, respectively. The copolymers exhibited no light scattering, and the film was very transparent. The glass transition temperatures of the PFPMI-co-MMA were in the range of 140 °C-180 °C with the PFPMI content from 18.8 to 65 mol% and the copolymers obtained have high thermal stability (∼370 °C). The water absorption of PFPMI-co-MMA was greatly reduced as compared with that of pure PMMA.