Fully Chemical Recyclable Poly(γ-butyrolactone)-based Copolymers with Tunable Structures and Properties

The emerging chemical recyclable polymers,such as poly(γ-butyrolactone)(PGBL)and poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),provide a good solution to the plastic pollution.However,these homopolymers suffer from limited structures and properties.Herein,we reported a fully chemical recyclable copolymer P(GBL-co-((R)-M))through ring-opening copolymerization(ROCOP)of GBL and(R)-M.By employing organomagnesium as the catalyst and regulating the reaction conditions,the chemical structures of copolymers were wellcontrolled(GBL content=13%-78%,Mn=6560-15600 g/mol,DM=1.08-1.59).The resultant P(GBL-co-((R)-M))exhibited fully chemical recyclability,which rapidly and quantitatively depolymerized into initial GBL and(R)-M monomer through chemolysis.By varying GBL content,tunable thermal properties were achieved for P(GBL-co-((R)-M)).The onset decomposition temperatures of copolymers varied from 193°C to 234°C.A linear evolution of glass transition temperature(T_(g))of P(GBL-co-((R)-M))versus GBL content was obtained as following equation of Tg=-1.06×GBL mol%×100+39.6.We hope that the reported fully chemical recyclable copolymers with tunable structures and properties would serve as the candidate material for sustainable applications.

IONIC CONDUCTIVITY OF POLY (β-ALKOXYCARBONYLETHYLMETHYLSILOXANE)-LiClO_4 CROSSLINKED FILMS

Poly (β-carboxyethylmethylsiloxane)-LiClO_4 and poly (β-alkoxylethylmethylsiloxane)-LiClO_4 crosslinked fllms have been prepared. The ionic conductivity of the films depends on the polymer species, concentration of lithium perchlorate, temperature and content of crosslinking agent. The effect of high polar organic solvent 1, 4-butyrolactone on the ionic conductivity and mechanical properties of poly (β-carhoxyethylmethylsiloxane )-LiClO_4 system was also investignied.

PVDF-HFP-SN-based gel polymer electrolyte for high-performance lithium-ion batteries

Gel polymer electrolytes(GPEs)have attracted extensive attention in lithium-ion batteries due to their high security and excellent electrochemical performance.However,their inferior Li-ion transference number,low room-temperature ionic conductivity,and poor long cycle stability raise challenges in practical applications.Herein,a flexible poly(vinylidene fluoride-cohexafluoropropylene)-butanedinitrile(PVDF-HFP-SN)-based GPE(PSGPE)is synthesized successfully by a general immersion precipitation method.The resultant PSGPEs have numerous connecting pores to ensure sufficient space for liquid electrolytes.Moreover,the reduced crystallinity of PVDF-HFP and the high polarity of SN can reduce the energy barrier of Li-ions shuttling between pores.The synergistic effect possesses a high ionic conductivity of 1.35 mS·cm^(-1)at room temperature with a high Li-ion transference number of 0.69.The PVDF-HFP-SN-based GPE is applied in a LiFePO_(4)/graphite battery,which can realize stable cycling performance for 350 cycles and good rate performance at room temperature.These results demonstrate that the novel PSGPE possesses advantage in simplified production process,which can improve the practicability of gel polymer lithium-ion batteries.

PPC-based Reactive Hot Melt Polyurethane Adhesive(RHMPA)--Efficient Glues for Multiple Types of Substrates

Tens of billion metric tons of anthropogenic CO_2 discharged from the burning of fossil fuels lead to an enormous environmental and resource burden. It is charming to transform CO_2 to desirable, economical chemicals and materials. Poly（propylene carbonate）（PPC） is an emerging CO_2-based material. Herein, we report the design, synthesis and characterization of the reactive hot melt polyurethane adhesive（RHMPA） based on PPC polyol. The resultant RHMPAs exhibit good adhesion properties to multiple substrates including plastics（PC, PMMA, ABS） and metals（aluminium, steel）, which is comparable to or even better than conventional RHMPAs prepared from petro-based polyol. Furthermore, the PPC-based RHMPAs have tunable mechanical properties, and are thermally stable in the typical working range of bonding process（up to 270 °C）. The study is expected to expand the applications of PPC and provide a new type of CO_2-based renewable and eco-friendly materials.