International Journal of Polymer Analysis and Characterization最新文献

In this work, glyceryl starch was prepared by changing the reactant ratio (v/w) of etherifying agent/starch using chlorinated glycerol as etherifying agent. The molar substitution of glyceryl starch was determined. The modified colorimetric method for the determination of molar substitution was described. The glyceryl starch was characterized by using FT-IR and ¹H NMR spectroscopy. Experimental analyses were performed to investigate the effect of dihydroxypropylation on a range of starch properties, including degree of crystallinity, granule morphology, paste clarity, and retrogradation stability and compare them with those of the native corn starch.

Hybrid composites are in increasing demand for structural applications. The created composite material is anticipated to possess fundamental qualities and a typical load-bearing capacity. The development of a hybrid composite hemp-epoxy polymer material with carbon and/or basalt fiber reinforcement is proposed in this study. With carbon fiber at 6%, basalt fiber at 6%, and carbon-basalt at 2 + 4% in the reinforcement, the weight percentage of the fiber reinforcement was altered for 15, 20, and 25% of hemp fiber in the composite. Additionally, natural fillers like coconut shell powder and calcium carbonate were incorporated into the matrix material. To create the composite with various combinations of fiber reinforcement, industrial standards processes were followed. In comparison to other compositions, the hemp-carbon fiber sample (A3) has a maximum strength of 104 MPa. The same composition also has a maximum stiffness of 197 N/mm, which may be attributed to the matrix material’s high bonding strength (67 weight percent). The shore hardness of the hemp-carbon fiber composite is likewise at its highest, falling between 90 and 98 on the hardness scale. The results revealed that composites composed of carbon and hemp fibers have superior mechanical characteristics to basalt fiber reinforcement. To investigate the material behavior, an electron microscope will be used to examine the cracked surfaces. The material will be suggested for use in structural applications based on the findings.

In this paper, the structural, morphological, and mechanical properties of Edgeworthia chrysantha phloem fibers are characterized. The chemical composition of Edgeworthia chrysantha mainly includes cellulose (47.13%), hemicelluloses (15.20%), and lignin (7.30%). X-ray diffraction analysis shows that Edgeworthia chrysantha phloem fiber has high crystallinity (76.38%) and small grain size (3.13 nm). Thermogravimetric analysis shows that the maximum degradation temperature of Edgeworthia chrysantha phloem fiber is 351 °C. The results of scanning electron microscopy and atomic force microscopy show that Edgeworthia chrysantha phloem fiber has an obvious hierarchical structure and a relatively rough surface. Additionally, the elastic modulus (6.04–15.21 GPa) and hardness (0.17–0.88 GPa) of Edgeworthia chrysantha phloem fiber were measured by nanoindentation. The result provided a theoretical basis for the high-value application of Edgeworthia chrysantha phloem fibers, especially in papermaking, textiles, fiber-reinforced material and other applications.

The spherulitic morphology and crystallization behaviors of binary crystalline blends of poly(butylene terephthalate) (PBT) and polyarylate (PAr), based on bisphenol A, (27:73 isophthalic:terephthalic acids), are investigated herein. PBT and PAr crystallize simultaneously or sequentially; various crystallization behaviors and morphologies are observed. In the PBT-rich blends, PAr does not crystallize; the PBT spherulites coarsen as the PAr concentration increases. Non-crystallizable PAr is trapped inside the spherulites. The PBT spherulitic growth rate decreases when PAr is added and remains constant thereafter. For the 50/50 blends, PBT and PAr crystallize simultaneously, and their spherulites co-exist separately. The spherulitic growth rate of PBT increases with time while PAr is crystallizing, but it remains constant if PAr crystallizes prior. At a crystallization temperature of 250 °C, only PAr crystallizes; the non-crystallizable PBT is expelled from the PAr spherulites because the crystallization rate of PAr is low. The spherulites of PAr do not fill the space in the final crystallization stage. The crystallization rate of the binary crystalline PBT/PAr blends was notably influenced by the prior crystallization of the other component, and was due to the change of the amorphous composition in addition to the constraints of the crystals on the chain mobility.

Prevention and control of calcium sulfate scale formation and microbial growth accumulation in water handling systems is one of the challenging operations to avoid corrosion and flow restriction through equipment. This paper examines modified low-molecular-weight Maleic Anhydride (MAn) copolymerized by Acrylamide (AAm), which was successfully synthesized, developed, and analyzed as a multifunctional non-phosphorous antiscalant to overcome these problems. The structure, morphology, and thermal property of poly(MAn-co-AAm) were characterized. The intended structure and copolymerization were confirmed through GPC, FT-IR, SEM, and EDX analyses. The high thermal resistivity up to 400 °C was observed via TGA analysis. The standard NACE TM0374 methodologies were applied to evaluate the scale controlling capacity of poly(MAn-co-AAm) at various dosages (1–20 ppm), temperatures (50–90 °C), and regular intervals of 24–72 h. Interestingly, for low values of poly(MAn-co-AAm), efficiency was found 100% at the third level within the standard state. Further SEM and XRD analyses emphasized the validity of successful inhibition of calcium sulfate scale formation in comparison with other antiscalant agents, even at very low concentrations. In addition, antibacterial properties of poly(MAn-co-AAm) were investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results revealed that the developed copolymer possesses a wide antibacterial activity against both Gram-negative and Gram-positive bacteria. With this in mind, poly(MAn-co-AAm) is believed to be an effective and economical multifunctional antiscalant in cooling water treatment systems.

Aromatic naphthalene thermotropic liquid crystal copolyesters (N-TLCP) have strong intermolecular forces and possess excellent comprehensive properties. In this study, the N-TLCP/MWCNT nanocomposites derived from 6-hydroxy-2-naphthoic acid (HNA), 2,6-naphthalene dicarboxylic acid (NDA), terephthalic acid (TA), 4,4′-dihydroxy biphenyl (BP) and carboxyl MWCNT were prepared via in situ “one-pot” melt polymerization method. The structure and properties of N-TLCP/MWCNT composites were fully analyzed. The interaction between MWCNT and TLCP matrix was confirmed by FTIR, XPS, Raman spectrum and rheometric measurements; and the strong interaction was observed for addition of a small amount of MWCNT (<0.5 wt%), which was attributed to the fact that the functional group COOH on the surface of MWCNTs enhances the dispersion state of the CNTs and molecular interaction through hydrogen bond/chemical covalent bonds. As a result, the glass transition temperature, melting temperature, thermal stability and mechanical properties of the N-TLCP/MWCNT composite was improved. However, more addition of MWCNT would tend to aggregate and impact the molecular weight and structure of the N-TLCP by the chemical reaction between its COOH group and OH group of the N-TLCP, which is not favor for improving the mechanical properties.