超临界二氧化碳

Synthesis of silver–polystyrene nanocomposite particles using water in supercritical carbon dioxide medium and its antimicrobial activity

由 ty10086 提交于周四, 08/26/2021 - 13:43

Abstract(#br)A novel method based on ex situ dispersion of silver nanoparticles within the monomers and subsequent emulsion polymerization using water-in-sc-CO 2 medium is introduced in this paper. Silver nanoparticles were synthesized by chemical reduction of silver nitrate using sodium borohydrate as a reducing agent and polydimethylsiloxane (PDMS) as a stabilizer in the water-in-sc-CO 2 medium.

Highly active and reusable palladium nanoparticle catalyst stabilized by polydimethylsiloxane for hydrogenation of aromatic compounds in supercritical carbon dioxide

由 ty10086 提交于周四, 08/26/2021 - 13:43

Abstract(#br)This study describes a hydrogenation method for degrading polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in supercritical carbon dioxide catalyzed by palladium nanoparticles stabilized in polydimethylsiloxane (Pd/PDMS). The process of synthesizing metal nanoparticles embedded in PDMS polymers involves the preparation of a homogenous mixture of metal salt, silicone elastomer, and a curing agent, followed by hydrogen reduction.

Permeation of supercritical CO 2 through dense polymeric membranes

由 ty10086 提交于周四, 08/26/2021 - 13:15

Abstract(#br)Supercritical carbon dioxide (scCO 2 ) is used in the food industry as a water-extracting drying agent. Once saturated with water, the scCO 2 needs to be regenerated. A promising way of drying scCO 2 is by using H 2 O permeable membranes. Ideally, these membranes demonstrate low CO 2 permeability. Here, we investigated the CO 2 permeability of three types of dense membranes, Nafion, Natural Rubber and PDMS, of which the latter in more detail because of its ease of handling.

超临界CO2对溶解水透过PDMS膜的影响

由 ty10086 提交于周四, 08/26/2021 - 13:10

文摘( # br )在超临界二氧化碳( scCO2 )条件下通过致密的聚二甲基硅氧烷( PDMS )进行水蒸气渗透，压力高达185bar，以评价scCO2作为干燥剂对常规干燥过程中易发生产品劣化的新鲜产品脱水的再生能力。本研究实验考察了在亚超临界CO2存在下，浓差极化对H2 O蒸汽透过致密PDMS膜的影响。将结果与含N2而不含CO2的体系进行了比较。( # br )对于CO2体系，在90bar时，随着进料压力的增加，不考虑膜层阻力的残馀传质阻力下降为零。这是进料本体和渗透液H2 O含量趋同的结果，导致进料边界层内主要H2 O输运机制由扩散转变为对流。这里H2 O和CO2分子以可比的速度向膜表面输送。对于含N2的体系，由于即使在高压下，H2 O和N2之间的传输速度仍保持着明显的差异，因此出现了相反的趋势。因此，通过PDMS膜的水汽输送速率受基质流体类型( CO2或N2 )的控制。

Fabrication of porous film based on poly(2,6-dimetyl-1,4-phenylene ether) block copolymer by supercritical carbon dioxide treatment

由 ty10086 提交于周四, 08/26/2021 - 12:58

Abstract\n\t\t\t\t\n\t\t\t\t\tThe block copolymer poly(2,6-dimethyl-1,4-phenylene ether)-\n\t\t\t\t\t\tb-polydimethylsiloxane (PPE-\n\t\t\t\t\t\tb-PDMS) was prepared via hydrosilylation between poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and polydimethylsiloxane (PDMS) homopolymers. The formation of block copolymer was confirmed by \n\t\t\t\t\t\t1H NMR and DSC analyses. The block copolymer films were treated by supercritical carbon dioxide (scCO\n\t\t\t\t\t\t2) at moderate temperatures under high pressure of 25\n\t\t\t\t\t\tMPa for 2\n\t\t\t\t\t\th followed by depressurization.