Lithium Polyacrylate (LiPAA) as an Advanced Binder and a Passivating Agent for High‐Voltage Li‐Ion Batteries

Intensive studies of an advanced energy material are reported and lithium polyacrylate (LiPAA) is proven to be a surprisingly unique, multifunctional binder for high‐voltage Li‐ion batteries. The absence of effective passivation at the interface of high‐voltage cathodes in Li‐ion batteries may negatively affect their electrochemical performance, due to detrimental phenomena such as electrolyte solution oxidation and dissolution of transition metal cations. A strategy is introduced to build a stable cathode–electrolyte solution interphase for LiNi_0.5Mn_1.5O₄ (LNMO) spinel high‐voltage cathodes during the electrode fabrication process by simply using LiPAA as the cathode binder. LiPAA is a superb binder due to unique adhesion, cohesion, and wetting properties. It forms a uniform thin passivating film on LNMO and conducting carbon particles in composite cathodes and also compensates Li‐ion loss in full Li‐ion batteries by acting as an extra Li source. It is shown that these positive roles of LiPAA lead to a significant improvement in the electrochemical performance (e.g., cycle life, cell impedance, and rate capability) of LNMO/graphite battery prototypes, compared with that obtained using traditional polyvinylidene fluoride (PVdF) binder for LNMO cathodes. In addition, replacing PVdF with LiPAA binder for LNMO cathodes offers better adhesion, lower cost, and clear environmental advantages.     

Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two‐phase polymer systems

Safety concerns related to the increasing and widespread application of synthetic coloring agents have increased the demand for natural colorants. Fungi have been employed in the production of novel and safer colorants. In order to obtain the colorants from fermented broth, suitable extraction systems must be developed. Aqueous two‐phase polymer systems (ATPPS) offer a favorable chemical environment and provide a promising alternative for extracting and solubilizing these molecules. The aim of this study was to investigate the partitioning of red colorants from the fermented broth of Penicillium purpurogenum using an ATPPS composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA). Red colorants partitioned preferentially to the top (PEG‐rich phase). In systems composed of PEG 6,000 g/mol/NaPA 8,000 g/mol, optimum colorant partition coefficient (K_C) was obtained in the presence of NaCl 0.1 M (K_C = 10.30) while the PEG 10,000 g/mol/NaPA 8,000 g/mol system in the presence of Na₂SO₄ 0.5 M showed the highest K_C (14.78). For both polymers, the mass balance (%MB) and yield in the PEG phase (%η_TOP) were close to 100 and 79%, respectively. The protein selectivity in all conditions evaluated ranged from 2.0–3.0, which shows a suitable separation of the red colorants and proteins present in the fermented broth. The results suggest that the partitioning of the red colorants is dependent on both the PEG molecular size and salt type. Furthermore, the results obtained support the potential application of ATPPS as the first step of a purification process to recover colorants from fermented broth of microorganisms. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1295–1304, 2015     

羧基化聚丙烯酸酯接枝邻甲酚环氧丙烯酸树脂的合成

采用JF-220环氧树脂和丙烯酸反应合成邻甲酚环氧丙烯酸树脂(JFA),再将其和羧基化聚丙烯酸酯进一步反应制备羧基化聚丙烯酸酯接枝邻甲酚环氧丙烯酸树脂(CAJFA)。研究了催化剂、阻聚剂和反应温度对合成反应的影响,确定了每步反应的最佳合成条件,并且对JF-220树脂、JFA树脂和CAJFA树脂的结构进行了IR表征。     

A method for concentrating dilute solutions of macromolecules

A simple, inexpensive acrylate polymer which has a capacity to absorb 170 ml of water per g has been developed. It can be used to concentrate dilute solutions of macromolecules such as proteins, nucleic acids, and carbohydrates. The polymer absorbs only low-molecular-weight substances such as glucose, sucrose, and inorganic salts. It can replace the various conventional concentration methods. No special device or electricity is needed for the concentration. The inexpensive polymer, molded in the form of rods, can be very conveniently used as “disposable concentration sticks.”     

Viability and protein secretion from human Hepatoma (HepG2) cells encapsulated in 400-mum polyacrylate microcapsules by submerged nozzle-liquid jet extrusion

An interfacial precipitation process to encapsulate mammalian cells in hydroxyethyl methacrylate-methyl methacrylate (HEMA-MMA) microcapsules of approximately 750 in approximately m diameter was previously described. It was not possible to produce smaller capsules due to low shearing force. A new droplet generation scheme was developed by suspending the cell and polymer co-extrusion nozzle in a uniform co-axial fluid jet which enabled the production of 300 to 600-microm diameter capsules. HepG2 hepatoma cells in 400-microm-diameter HEMA-MMA capsules were able to retain their metabolic activity during and after the encapsulation process. The in vitro secretion of plasma proteins alpha(1)-acid glycoprotein, alpha(1)-antitrypsin, and fibrinogen by the encapsulated cells was retained. The encapsulated cells secreted less fibrinogen (340 kD) relative to alpha(1)-acid glycoprotein (42kD), indicating the sieving effect (but not absolute cut-off) of the HEMA-MMA membrane. (c) 1994 John Wiley & Sons, Inc.     

四元共聚丙烯酸酯热熔压敏胶膜的合成研究

以丙烯酸-2-乙基己酯(2-EHA)、甲基丙烯酸甲酯(MMA)、丙烯腈(AN)和丙烯酰胺(AM)为共聚单体,采用预乳化法制备聚丙烯酸酯热熔胶,研究了单体质量分数配比,乳化剂质量分数、配比及乳化方式,引发剂质量分数,温度和滴加速度对反应及性能的影响。结果表明:2-EHA 50%,MMA 40%,AN 5%,AM 5%,复合乳化剂3.0%,引发剂过硫酸钾0.3%,80～85℃,反应4 h,丙烯酸酯橡胶分子量在10万以上时,制得的热熔压敏胶膜综合性能良好。     

Biodegradation and sorption properties of polydisperse acrylate polymers

Polyacrylate (PA), which is widely used in disposable diapers, is synthesized by polymerization and cross-linking of acrylate. During the synthesis, 3–6% of the polyacrylate polymers is not incorporated into the absorbent material, but remains soluble. If the soluble PA is mobilized from a landfill, it could enter the groundwater. Therefore, the biodegradation and adsorption properties of soluble polymers contained in PA are determined in this study. The soluble PA is highly polydisperse, and the fraction tested has a weight-average molecular-weight of 16,700 and a range extending from 10³ to 10⁵. Sand-column tracer tests show that about 1% of the polyacrylate is unadsorbed, but the remainder has a retardation factor that averages at least 58. Biodegradation kinetics are determined in completely mixed biofilm reactors having a methanogenic consortium grown on glucose. The polyacrylate fraction, as well as glucose and acrylate, are removed and mineralized to CO₂. The Monod parameters for the polyacrylate are: maximum specific rate of substrate utilization = 0.0016 gC/g biomass-day, and half-maximum-rate concentration = 0.79 gC/m³. Although these kinetics are much slower than for glucose and acrylate, significant degradation and mineralization are observed.     

Biological fate of a polydisperse acrylate polymer in anaerobic sand-medium transport

Soluble polyacrylate (PA), a polydisperse mixture of polyacrylate polymers, is strongly adsorbed and biodegradable. Biotic fate studies were carried out with once-through columns containing sand colonized with anaerobic biomass previously grown in a methanogenic fluidized bed. A fraction of soluble PA having a weight-average molecular weight of 16,700 and a range of molecular weight from 10³ to 10⁵ was biologically removed and mineralized to CO₂. Due to its polydisperse nature, the breakthrough curve had a gradual increase to an apparent steady-state removal of approximately 60% near one day when the liquid detention time was 21 minutes. Modeling successfully explained the observed breakthrough result when the fraction was divided into components having a wide range of retardation factors (R): about 25% was strongly adsorbed (R=200 and 500), 45% was moderately adsorbed (R=50 and 100), and 30% was weakly adsorbed (R=1–10). In this study, in which active biomass already was present from utilization of a primary substrate (glucose here), equilibrium adsorption increased the time to breakthrough, which also reduced the exiting concentration by increasing the substrate contact time.     

接枝共聚法合成多彩水晶花泥

采用水溶性引发剂,以N'N'-亚甲基双丙烯基酰胺为交联剂,表面活性剂为助剂进行丙烯酸和彩色聚丙烯酸脂接枝共聚,合成多彩水晶花泥。制得的共聚物可吸水100倍以上,形成水凝胶呈水晶多棱结构,色彩艳丽且色泽牢固、不溶于水、无毒、无污染,可用于家庭花卉无土培养、室内插花装饰等。本文讨论引发剂、交联剂、助剂等合成条件对共聚物性能的影响。     

Metabolic activity of CHO fibroblasts in HEMA-MMA microcapsules

Chinese hamster ovary (CHO) fibroblast cells were microencapsulated in polyacrylate membranes (HEMA-MMA: 75% HEMA) via an interfacial precipitation process. The CHO cells were observed to grow in large aggregates, attached to each other instead of to the capsule wall. When CHO cells were encapsulated at high density (4 x 10(6) cells/mL), the initial metabolic activity in microcapsules, as determined by the MTT assay, correlated with the polymer-cell extrusion ratio, presumably because of the dependence of encapsulation efficiency on the relative flow rates. However, there was a large variation in the metabolic activity among individual microcapsules throughout the present study. Capsules with low encapsulation efficiency (at a "seeding" density of 4 x 10(6) cells/mL) exhibited a rapid increase in the metabolic activity during the following week. When CHO cells were encapsulated at low density (4 x 10(5) cells/mL), there was only a small increase in the metabolic activity. Only a small fraction ( approximately 5%) of the capsules exhibited a high level of metabolic activity and 40% of the capsules exhibited undetectable metabolic activity even after 2 weeks. We conclude that CHO cells, which served as model cells, survive the encapsulation process and retain an active metabolic state once enclosed by the HEMA-MMA membranes. However, the resultant microcapsules are extremely heterogeneous in the amount of retained metabolic activity.