The Crystallization Behavior of L-Poly(lactic acid)/Polypropylene Blends:The Acceleration for Both L-Poly(lactic acid)and Polypropylene

For a polymer/polymer dismissible blend with two crystallizable components,the crystallization behavior of different components and the reciprocal influences between different crystals are interesting and important,but did not investigate in detail.In this study,the L-poly(lactic acid)/polypropylene(PLLA/PP)blends with different weight ratios were prepared by melt mixing and the crystallization behavior of the blends were investigated.Results showed that the crystalline structures of PLLA and PP were not altered by the composition.For the crystallization of PLLA,both the diffusion of chain segments and crystallization rate were enhanced under the existence of PP crystals.For the crystallization of PP,its crystallization rate was depressed under the existence of amorphous PLLA molecular chains.When the PP crystallized from the existence of PLLA crystals,although the diffusion rate of PP was reduced by PLLA crystals,the nucleation positions were obviously enhanced,which accelerated the formation of PP crystals.This investigation would supply more basic data for the application of PLLA/PP blend.

Double Off-line Two-dimensional Liquid Chromatography for Separation and Identification of Compounds in Salvia Miltiorrhiza(Danshen)

Background: Danshen is an important traditional Chinese medicine(TCM) used for the treatment of cardiovascular and cerebrovascular diseases. Separation and analysis of its components have been widely investigated. However, the systematical two dimensional liquid chromatography(2D-LC) methods have not been developed to comprehensively separate and characterize its components.Objective: In this work, double off-line 2D-LC methods were aimed to develop for the systematical separation of compounds from Danshen.Methods: Using solid phase extraction(SPE), the Danshen extract was divided into a medium-polar fraction(Sample I) and a weak-polar fraction(Sample Ⅱ) according to their polarities. Based on reversed-phase liquid chromatography(RPLC) and hydrophilic interaction liquid chromatography(HILIC) modes, a 2D-HILIC × RPLC system and a 2D-RPLC × RPLC system were designed for the separation of Sample Ⅰ and Sample Ⅱ, respectively. According to reversed-phase and HILIC columns selectivities characterized in our previous reports, ZIC-HILIC and XTerra C18 were employed to build the 2D-HILIC × RPLC system and Click TE-CD and XTerra C18 for the 2D-RPLC × RPLC system,respectively.Results: The 2D-HILIC × RPLC and 2D-RPLC × RPLC systems exhibited excellent orthogonality for the separation of Sample Ⅰ and Sample Ⅱ,respectively. Their orthogonalities were 88.42% and 63.24%. Based on these double 2D-LC systems combined with mass spectrometry, at least 200 compounds were found and 33 compounds of them were identified, including 16 phenolic acids and 17 diterpenoid quinines.Conclusion: These results suggest that these two off-line 2D-LC methods are effective for the separation and characterization of components in Danshen.

Orientation controlled photogenerated carriers on selfsupporting CdS/Ni_(3)S_(2) paper toward photocatalytic hydrogen evolution and biomass upgrading

The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems.Present photocatalytic system mainly employs powder photocatalysts,which makes their recovery reliant on expensive separation processes and severely limits their industrial application.Herein,we constructed a novel CdS/Ni_(3)S_(2)heterostructure using free-standing and flexible nickel fiber paper as the matrix.The regulated energy band structure achieves effective electron–hole separation.The as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H_(2)evolution reaction under visible-light irradiation,with an H_(2)production rate of5.63μmol·cm^(-2)·h^(-1)(14.1 mmol·g^(-1)cat·h^(-1)according to the catalyst loading content).Additionally,the otherwisewasted excited holes simultaneously drive organic transformations to yield value-added organic products,thus markedly improving the photocatalytic H_(2)evolution rate.Such a photocatalytic system is scaled up further,where a self-supported 20 cm×25 cm sample achieves a champion H_(2)production rate of 60-80μmol·h^(-1)under practical sun irradiation.This newly developed self-supported photocatalyst produces opportunities for practical solar H2production with biomass upgrading.

Polyoxometalates-derived nanostructures for electrocatalysis application

The conversion of intermittent renewable electrical energy to chemical energy is of great importance which can not only mitigate current energy and environmental crisis but also contribute to the ongoing carbon neutrality national strategy.Electrocatalysis is serving as a low-carbon conversion technology that enables green and efficient energy conversion mainly through hydrogen evolution reaction(HER),carbon dioxide reduction reaction(CO_(2)RR),and nitrogen reduction reaction(NRR).The core of electrocatalysis is the design and construction of low-cost high-activity and high-stability electrocatalyst to drive reaction thermodynamics and kinetics.The employment of polyoxometalates(POMs)as platforms or precursors to construct different types of electrocatalysts has been widely reported.Herein,we systematically summarized the recent advances in POM-derived nanostructures for electrocatalysis application.The strategies for precursor design and electrocatalyst synthesis were briefly introduced.The morphology control,phase control,composite modulation,and heterostructure engineering in POM-derived nanostructures were presented in detail.The structure–activity relationship of POM-derived nanostructures is fully discussed for HER CO_(2)RR,and NRR applications.Finally,the current challenges and future outlooks of POM-derived nanostructures are summarized to provide insights toward high-efficiency electrocatalysts for energy conversion technologies.