Summary: Solid‐state processing for the preparation of poly(p‐phenylenesulfide) (PPS‐) based nano‐composites having finely dispersed layered fillers was conducted. The mixture of PPS and organically modified layered filler (OMLF) (95/5 wt./wt.) was subjected to the processing using thermostated hot‐press at 150 °C, below Tm of PPS (i.e., PPS is still at the solid‐state), and applying pressures of 33 MPa for 30 s. The mixture exhibited disorder and delaminated layer structure with the thickness of 10–20 nm into the PPS matrix. In contrast, a nano‐composite prepared by melt compounding at 300 °C for 3 min showed large stacked silicate layers in the PPS matrix. The processing led to delamination of the silicate layers and attained the discrete dispersion.
TEM bright field image and FFT spectrum of a solid‐state processed PPS nano‐composite. 相似文献
The steric tacticity of polyphenylsilsesquioxanes (PPS) was studied by exeimer fluorescence spectroscopy. It was found that the fluorescence of PPS come mainly from its intramolecular excimers, The experimental results indicated that the steric-structure of PPS is most probably cisisotactic rather than the cis-syndiotactic as suggested in the literature. With the increase in defect content monomer fluorescence intensity increases because of the enhanced mobility of phenyl groups. Molecular weights and molecular weight distributions do not affect the fluorescence spectra of PPS. 相似文献
The curing and degradation behaviour of poly(phenylene sulphide) (PPS) and poly(2-methyl phenylene sulphide) (PMPS) in air and nitrogen has been studied. Curing studies have been made utilising assessment by solubility, indentation hardness, dynamic mechanical properties and heat of crystallisation studies. The results are critically discussed in terms of their ability to assess the degree of curing achieved.Degradation studies with product analysis by gas-liquid chromatography, infrared spectroscopy and chemical tests are reported and mechanisms of curing and degradation suggested and tested by studies on possible intermediates. The degradation behaviour of PMPS is complicated by oxidative and thermal reactions associated with the methyl substituent. 相似文献
Photochemical properties of photoinduced ω-bond dissociation in p-phenylbenzoylbenzyl phenyl sulfide (PPS) having the lowest triplet state (T1) of π,π* character in solution were investigated by time-resolved EPR and laser flash photolysis techniques. PPS was found to undergo photoinduced ω-bond cleavage in the excited lowest singlet state (S1(n,π*)) with a quantum yield (Φrad) of 0.15 for the radical formation, which was independent of excitation wavelengths. Based on the facts of the observation of the absorption spectrum of triplet PPS upon triplet sensitization of xanthone, and absence of CIDEP signal, ω-cleavage was shown to be absent in the T1(π,π*) state of PPS. Considering the electronic character of the excited and dissociative states of PPS, a schematic energy diagram for the ω-bond dissociation of PPS was shown. 相似文献
Red emissive carbon dots(CDs) powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%. This method is safe and convenient, for it needs neither high pressure reactors nor complicated post-treatment procedures. The as-prepared carbon dots powder exhibited strong red fluorescence with excitation-independent behavior. XPS measurement and PL spectra suggest that such red fluorescence arise from boron-doped structures in CDs, which increases along with the boron concentration on CDs surface but decreases when the concentration quenching effect takes place. To overcome the aggregation induced fluorescence quenching of the solid CDs powder,the conventional methods are dispersing CDs into a large amount of inert substrates. But our present work provides a new strategy to realize strong red fluorescence of CDs in solid state. As a result, such carbon dots powder works well for latent fingerprint identification on various material surfaces. 相似文献