Series Of Multiblock Copolymers Research Articles

Boosting electrochemical performance by regulating rigid-flexible microphase separation of multiblock copolymers

The growth of lithium dendrites and associated safety issues hinder the further development of liquid lithium metal batteries. A novel rigid-flexible multiblock copolymer PBC-mb-PBS was successfully synthesized based on molecular design. Incorporating crystalline rigid phase polybutylene succinate (PBS) into PBC-mb-PBS significantly enhances its tensile strength and low-temperature toughness through physical crosslinking. The flexible polydibutyl 2-(2-cyanoethyl)malonate (PBC) phase with side-chain cyano groups facilitate ionic conduction, forming a LiN-rich stabilized interfacial layer, thereby improving oxidative stability and high-voltage cathode compatibility. A series of multiblock copolymers with varying segment lengths were synthesized to balance mechanical properties and ionic conductivity by adjusting microphase separation. The quasi-solid-state polymer electrolyte (QSPE), derived from PBC-mb-PBS with the molar block ratio of 0.42, exhibits optimal electrochemical performance with ionic conductivity of 6.20 × 10−5 S cm−1 at 30°C and 4.22 × 10−4 S cm−1 at 60°C. Due to its bicontinuous microphase structure, it also shows excellent mechanical strength and promotes uniform lithium deposition at high current densities. Li//LiFePO4 and Li//LiNi0.83Co0.05Mn0.12O2 cells demonstrate high capacity retention, confirming the potential of this polymer electrolyte in high-voltage applications. This design strategy offers insights for developing quasi-solid-state lithium metal batteries with superior overall performance.

Building Bridges by Blending: Morphology and Mechanical Properties of Binary Tapered Diblock/Multiblock Copolymer Blends

AbstractThis work explores the scope and limitations of enhancing the poor mechanical properties of diblock copolymers by blending with tapered multiblock copolymers of styrene (S) and isoprene (I), P(I‐co‐S)n. Blending of different tapered diblock copolymers (n = 1; Mn = 80 and 240 kg mol−1, 50 wt% polyisoprene (PI) units, lamellar morphologies) affords brittle materials with low elongation at break. An increasing degree of phase separation from (i) miscible P(I‐co‐S)/P(I‐co‐S)n copolymer blends, to (ii) partially miscible and (iii) finally immiscible blends is studied. The effect of miscibility on the mechanical properties is studied for two diblock copolymers (Mn = 80 and 240 kg mol−1, domain spacing of 38 and 77 nm, respectively), blended with a series of multiblock copolymers P(I‐co‐S)n (n = 2–5; domain spacing of 42 to 20 nm) of similar molecular weight. Increasing disparity in the domain spacing results in partially miscible and finally immiscible blends. Immiscibility causes lower elongation at break, albeit superior tensile properties compared to the pure tapered diblock copolymers are maintained. The study shows that the addition of a minor fraction of multiblock copolymers to diblock copolymers is a versatile method toward improved mechanical properties, while retaining an ordered nanophase‐separated morphology.

Characterization of Langmuir Films Prepared from Copolyesterurethanes Based on Oligo(ω‐pentadecalactone) and Oligo(ε‐caprolactone) Segments

A series of multiblock copolymers (PDLCL) synthesized from oligo(ω‐pentadecalactone)diol (OPDL) and oligo(ε‐caprolactone)diol (OCL), which are linked by 2,2(4),4‐trimethyl‐hexa­methylene diisocyanate (TMDI), is investigated by the Langmuir monolayer technique at the air–water interface. Brewster angle microscopy (BAM) and spectroscopic ellipsometry are employed to characterize the polymer film morphologies in situ. PDLCL containing ≥40 wt% OCL segments form homogeneous Langmuir monofilms after spreading. The film elasticity modulus decreases with increasing amounts of OPDL segments in the copolymer. In contrast, the OCL‐free polyesterurethane OPDL‐TMDI cannot be spread to monomolecular films on the water surface properly, and movable slabs are observed by BAM even at low surface pressures. The results of the in situ morphological characterization clearly show that essential information concerning the reliability of Langmuir monolayer degradation (LMD) experiments cannot be obtained from the evaluation of the π–A isotherms only. Consequently, in situ morphological characterization turns out to be indispensable for characterization of Langmuir layers before LMD experiments. image

Synthesis and Characterization of Sulfonated Poly(Arylene Ether Sulfone) Multiblock Copolymers for Proton Exchange Membrane

A series of multiblock copolymers based on sulfonated poly (arylene ether sulfone) (bSPAES-SF) with highly rigid hydrophilic sulfonate blocks and flexible hydrophobic blocks were successfully synthesized by the condensation of sulfonated decafluorobiphenyl-terminated oligomers and the hydroxyl-terminated oligomers. The former oligomers were sulfonated by fuming sulfonic acid. The bSPAES-SF membranes with IEC of 1.26-1.70 mmol/g exhibited high proton conductivity, hydrolytic and dimensional stability.

Characterization of Multiblock Sulfonated Poly(Arylene Ether Sulfone) as Proton Exchange Membranes

A new series of hydrophobic-hydrophilic multiblock sulfonated poly (arylene ether ketone)-b-poly (arylene ether ketone) copolymers were successfully synthesized and evaluated for use as proton exchange membranes (PEMs). The membrane properties of block copolymers including ion exchange capacities (IECs), water uptake and proton conductivities were characterized for the multiblock copolymers and compared with random sulfonated poly (arylene ether) s and other multiblock copolymer membranes at similar ion exchange capacity value. This series of multiblock copolymers showed moderate conductivities up to 0.063 S/cm at 80 °C with very low water uptake of 19%. Therefore, they are considered to be promising PEM materials for fuel cells.

Partly fluorinated poly(arylene ether ketone sulfone) hydrophilic–hydrophobic multiblock copolymers for fuel cell membranes

Hydrophilic–hydrophobic alternating poly(arylene ether ketone sulfone) multiblock copolymers, 6FK-BPSH100, were prepared by the synthesis and coupling of partly fluorinated hydrophobic poly(arylene ether ketone)oligomers (6FK) and disulfonated hydrophilic poly(arylene ether sulfone) telechelic oligomers (BPSH100), containing 3,3′-disulfonated-4,4′dichlorodiphenylsulfone (SDCDPS) as a source of ionomeric moieties. By precisely controlling the molecular weight and composition of the telechelic oligomers, a series of multiblock copolymers were prepared varying in block length and ion exchange capacity (IEC) for a comparative study. The resulting copolymers afforded tough and ductile membranes by solution casting from DMAc. Membrane properties of these copolymers were characterized with regard tointrinsic viscosity, thermal stabilities, morphology, water uptake, and proton conductivity. The results were compared to those of Nafion® and random copolymer BPSH35. The nanophase separated morphology developed in the membranes was illustrated by transmission electron microscopy (TEM), which account for enhanced proton conductivity at reduced relative humidity (RH). More importantly, film processing studies have demonstrated that a major advance in proton conductivity versus RH behavior and greatly reduced water uptake could be achieved via precise annealing experiments.

Synthesis and Characterization of Biodegradable Poly(ϵ-caprolactone)-b-Poly(L-lactide) and Study on Their Electrospun Scaffolds

A series of multi-block copolymers, poly(L-lactide)-b-poly (ϵ-caprolactone) (PLLA-b-PCL) were synthesized. The first step of the synthesis consisted of the transesterification between the PLLA and 1,4-Butanediol, followed by the copolymerization of PLLA-diols and PCL, using isophorone diisocyanate (IPDI) as a coupling agent. The synthesized polymers were characterized by Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). PLLA/PCL block copolymers were electrospun into ultrafine fibers. The morphology of the electrospun fibrous scaffolds were investigated by Scanning Electron Microscopy (SEM). Results showed that the morphology and diameter of the fibers were affected by the electrospinning solution concentrationan and different weight ratio of PLLA/PCL. These electrospun PLLA-b-PCL fibrous membranes exhibited good flexibility and deformability. In comparison with the electrospun PLLA membrane, the electrospun fibrous membranes of PLLA-b-PCL demonstrated an enhanced elongation with still high tensile strength and Young's modulus to be beneficial for tissue engineering scaffolds.

Poly(ethylene terephthalate) modification with the monomer from renewable resources (in English)

An emerging problem related to the development of biodegradable polymers from renewable resources was brought up in this work. Modification of petrochemical-based poly(ethylene terephthalate)(PET) with the use of bio-based monomer, namely dilinoleic acid (DLA) was presented. Series of multiblock copolymers containing oligo-PET as hard segments and DLA as soft segments was obtained in typical process of PET synthesis via polycondensation from the melt. PET/DLA copolymers containing Wh=30-90 wt.% of hard segments were characterized with respect to their mechanical, thermal and processing properties. It was demonstrated that at high concentration of DLA (Wh=30-40 wt.%) materials are susceptible to hydrolytic degradation.

Synthesis and Characterization of Sulfonated‐ Fluorinated, Hydrophilic‐Hydrophobic Multiblock Copolymers for Proton Exchange Membranes

AbstractNanophase separated ionic‐hydrophobic block copolymers may be more suitable as proton exchange membranes than random copolymers. A series of multiblock copolymers, composed of alternating segments of fully disulfonated poly(arylene ether sulfone) and highly fluorinated poly(arylene ether sulfone), were synthesized from hydrophilic and hydrophobic telechelic oligomers having a variation of molecular weights. The high reactivity of the fluorinated oligomers made unnecessary the use of high reaction temperatures, and thus the coupling reactions may be free of ether‐ether interchange side reactions. The copolymers were characterized with regard to proton conductivity, water uptake and self‐diffusion coefficient of water, and the results were compared to those of Nafion and a partially disulfonated BPSH‐35 random copolymer.

Thermal properties of multiblock thermoplastic elastomerswith oligoamide soft blocks derived from dimerized fatty acid

Two series of multiblock copolymers, poly(ester-block-amide)s (PEA) and poly(amide-block-amide)s (PAA), with the same type of oligoamide soft block were obtained. Oligoamide soft block was prepared from dimerized fatty acid and 1,6-hexamethylenediamine. Oligo(butylene terephthalate) (PBT) was used as oligoester hard block in the first series and oligolaurolactam (PA12) was oligoamide hard block in the second one. The thermal and mechanical properties of these copolymers have been investigated as functions of temperature and the hard/soft block ratio. DSC and DMTA revealed that the copolymers behaved as thermoplastic elastomers.