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Graphite nanoparticles (GNPs) were introduced into poly(p-phenylene benzobisoxazole) (PBO) matrix to produce composites via in situ polymerisation. Films of various composites were fabricated through the solution casting method in methanesulfonic acid (MSA) with the help of two sand core plates. The interlayer spacing of GNPs increased slightly confirmed by XRD as a result of an expanding effect caused by continuously formed PBO chains between the graphene nanosheets of GNPs during polymerisation. Also, due to the uniform dispersion of GNPs into PBO matrix, composite films exhibited an improved tensile strength (258 MPa, 72% higher than that of pure PBO) with 5 wt% loading of GNPs fillers. The initial decomposition temperature of the composite is ∼630°C. Besides, benefitting from the interfacial polarisation in this conductive filler/polymer system, the dielectric constant of the composites with 10 wt% loading of GNPs reached 6.96, which were over two times higher than that of pristine PBO polymer (2.91).

Three pairs of bimetallic Schiff base aluminum complexes (1a–6a) with different tetraamine backbone bridging parts and bulky silyl-substituted moieties on salicylidene were synthesized. Using these complexes as catalysts for ring opening polymerisation (ROP) of racemic-lactide (rac-LA), systematical stereoselectivity and kinetic studies on ROP of rac-LA were carried out. The Gibbs free energy difference between homo-propagation and cross-propagation (ΔG≠) calculated by activation entropy and enthalpy showed that bulky substituents at the 3-position enhanced the stereoselectivity. And the kinetic study results indicated that bulkier substituents with more steric hindrance reduced the ROP reactivity. Moreover, these complexes could also be used for copolymerisation of rac-LA and e-caprolactone (e-CL). Copolymers of poly(LA-co-CL) with various monomer ratios were synthesized. Kinetic research on copolymerisation as well as microstructure analysis demonstrated that poly (LA-co-CL) achieved by these complexes were tapered block copolymers.

Aiming to disperse HA nanocrystals in a polymer matrix homogenously, uniform oil-soluble HA nanorods were synthesized via an oleic acid (OA)-assisted mixed-solvent thermal method, and then poly(lactic acid) (PLA)/HA nanorods nanocomposites were fabricated by using a solution method. The HA nanorods with an OA monolayer on the surface dispersed homogeneously in organic solvents and the dispersion in polymer solution was transparent and colloidally stable. TEM images showed that HA nanorods dispersed as single particles without aggregation in PLA matrix. The elongation at break of the composites increased from 4.24% to 8.79% by adding HA nanorods, whereas the tensile strength and Young's modulus were largely unchanged. HA nanorods accelerated evidently the PLA crystallization rate even at a low HA loading and induced a transition to an ordered crystalline morphology confirmed via non-iso/isothermal crystallization, the spherulitic morphology, calculations and wide-angle X-ray diffraction during heating and cooling cycles.

A newly synthesized aromatic sulfonate compound, complex 2 with formula of K2[H3COOC-C6H3(SO3)2]·2H2O(methyl 3,5-disulfo-benzoate dipotassium dihydrate) was synthesized and characterized by elemental analysis, infrared(IR) spectrometry, nuclear magnetic resonance(NMR) and crystal structure measurement. Single-crystal X-ray diffraction(XRD) revealed that complex 2 crystallized in the triclinic system with space group $$P_{\bar 1}$$ . Complex 2 was used as nucleating agent for poly(L-lactide)(PLLA). The crystallization of PLLA with powder of complex 2 was investigated by means of differential scanning calorimetry(DSC) and polarized optical microscopy (POM). The results prove that complex 2 was effective as nucleating agent for PLLA. It could accelerate crystallization by reducing the induction time and increasing the density of nuclei in the crystallization process. The half-time of crystallization(t 0.5) for pure PLLA was about 8 times longer than that of PLLA sample with 1.0%(mass fraction) of complex 2.

A new method for quantitative analysis of lactide has been developed by applying chemical kinetics to a HPLC system. The most important advance is its practical approach to the quantification of analytes that are unstable in the HPLC mobile phase. In HPLC analysis, anhydrous mobile phases cannot separate lactide from impurities, and only mixtures of water and organic solvent can achieve effective separation. By selecting conditions for testing and studying the kinetics of lactide hydrolysis, extensive experiments revealed that lactide degradation can be treated as a pseudo-first-order reaction under the given HPLC conditions, and lactide content or purity can be quantitatively determined. This method is practical for measuring the purity of the intermediate lactide in polylactic acid (PLA) production and the lactide content in PLA. When lactide content is high, the relative standard deviation (RSD) of the measurements is

Brown crystalline tricyclopentadienyl cerium tetrahydrofuranate (THF) complex (eta5-C5H5)3Ce(THF) was prepared by the reaction of (NH4)2Ce(NO3)6 with sodium cyclopentadienide (C5H5Na) in THF at molar ratio of 1:6. ErCl3.4THF reacts with potassium cyclooct

LnCL3 reacts with NaC5H5 and K2C8H8 to yield the complexes (η5-C5H5)Ln(η8-C8H8)·nTHF (Ln = Pr, Nd, n= 2; Ln = Gd, n= 1) and LnCl3 reacts with KC9H7 and K2C8H8 to yield the complexes (η5-C9H7)Ln(η8-C8H8)·2THF (Ln = Pr, Nd; η5-C9H7= indenyl); crystallography reveals (η5-C5H5)Pr(η8-C8H8)·2THF and (η5C9H7)Pr(η8-C8H8)·2THF not to possess the parallel ring sandwich structure.

The crystal and molecular structures of NdCl3· 4THF have been determined by the low temperature (−60 °C) X-ray diffraction method. NdCl3·4THF recrystallizes in the monoclinic space group P21/c with unit cell parameters a = 9.404(4), b = 21.591(5), c = 11.751(3) A, β = 111.03(3)°, Z = 4. The final R value is 0.039. Three chlorine atoms and four oxygen atoms from THF are coordinated with the central Nd(III) ion to give a pentagonal bipyramid polyhedron with coordination number 7, the average NdCl bond length is 2.674 A and NO 2.498 A. When combined with aluminum alkyls, NdCl3· 4THF is a highly effective catalyst for the polymerization of dienes. Relationships between complex structures and polymerization activities are discussed and the difference in polymerization activities between NdCl3 and NdCl3·4THF is related to their crystal stabilities.