Improvement of physical properties of crosslinked alginate and carboxymethyl konjac glucomannan blend films

Blend films from carboxymethyl konjac glucomannan and sodium alginate in different ratios were prepared by blending 4 wt % sodium alginate aqueous solution with 2 wt % konjac glucomannan aqueous solution. After crosslinking with 5 wt % calcium chloride aqueous solution, the blend films formed a structure of semi‐interpenetrating networks. The structure and physical properties of both uncrosslinked and crosslinked films were characterized by Fourier transformed infrared spectra (FTIR), differential thermal analysis (DTA), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests. The results indicated that the mechanical properties and the thermal stability of the films were improved by blending sodium alginate with carboxymethyl konjac glucomannan due to the intermolecular hydrogen bonds between sodium alginate and carboxymethyl konjac glucomannan. The crosslinked blend films with Ca²⁺, compared with uncrosslinked blend films, exhibited further improved physical properties due to the formation of a semi‐IPN structure. Furthermore, the degree of swelling of the crosslinked films was also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2554–2560, 2002     

Preparation and characterization of konjac glucomannan and sodium carboxymethylcellulose blend films

The novel blend films of konjac glucomannan (KGM) and sodium carboxymethylcellulose (NaCMC) were prepared by casting the mixed polymer aqueous solutions. The physical properties of the blend films from konjac glucomannan and sodium carboxymethylcellulose were investigated by using FT‐infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), differential thermal analysis (DTA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and measurements of mechanical properties. The experimental results showed that the occurrence of the interactions between KGM and NaCMC molecular chains through hydrogen bond formation, and the physical properties of the films largely depend on the blending ratio. The thermal stability, mechanical properties of both tensile strength, and elongation at break of the blend films were improved by blending KGM with NaCMC. The surface morphology of the films observed by SEM was consistent with the results mentioned above. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 26–31, 2001     

热塑性魔芋葡甘聚糖/聚己内酯共混物制备及表征

以资源丰富的天然可降解高分子材料魔芋葡甘聚糖(KGM)为原料, 以甲基丙烯酸甲酯和丙烯酸甲酯为单体,过硫酸铵为引发剂,合成了热塑性魔芋葡甘聚糖。将热塑性魔芋葡甘聚糖(TDKGM)和聚己内酯(PCL)熔融共混制备热塑性魔芋葡甘聚糖/聚己内酯共混物(TDKGM/PCL)。通过热重分析、扫描电镜、差示扫描量热仪(DSC)、XRD和万能力学试验机等对TDKGM/PCL共混物的结构和性能进行了分析表征。结果表明：共混物中热塑性魔芋葡甘聚糖对聚己内酯的结晶起到了成核剂的作用,使聚己内酯能在较高温度下开始结晶,并可明显提高共混物中聚己内酯相的结晶速度。TDKGM/PCL复合材料(20/80)的最大扭矩值为48.7 N·m,塑化时间在300 s以上,平衡扭矩在10.7 N·m,与PE相当接近,并且具有高达256.48%的断裂伸长率。     

Preparation and characterization of polylactide/thermoplastic konjac glucomannan blends

In this article, a new degradable thermoplastic konjac glucomannan (TKGM) was synthesized by graft copolymerization of vinyl acetate and methyl acrylate onto konjac glucomannan (KGM). Melt blending of polylactide (PLA) and TKGM has been performed in an effort to improve the processing and comprehensive mechanical properties of PLA and TKGM without compromising its degradability and biocompatibility. The miscibility, processing rheology, phase morphology, thermal properties, interaction, crystallization and mechanical properties of PLA/TKGM blends were investigated in detail. The thermal processing property of PLA/TKGM blend (60/40) was quite close to low density polyethylene (LDPE). As observed from the tan δ curves in dynamic mechanical analysis, all of the blends exhibit a single glass transition over the entire composition range, indicating that the blends were thermodynamically miscible. The TKGM exhibited a relatively broad endothermic peak at around 120 °C, which was lower than that of KGM. And an obvious glass-transition behavior was obtained around 26.6 °C. Furthermore, the PLA/TKGM blend (60/40) had a very high elongation at break of 234.8%, while the tensile strength remained as high as 36.5 MPa. And the PLA/TKGM blend (20/80) resulted in an even greater ductility with an elongation at break of 520.5% as compared with 14.1% for pure PLA. A substantial increase in the non-notched impact strength was also observed with the PLA/TKGM blend (20/80) demonstrating two times the impact strength of pure PLA.     

Miscibility and properties of blend materials from waterborne polyurethane and carboxymethyl konjac glucomannan

We prepared composite materials by blending waterborne polyurethane (WPU) and carboxymethyl konjac glucomannan (CMKGM) with CMKGM content from 15 to 80 wt % in an aqueous system. The structures and properties of the blend materials were characterized by FTIR, dynamic mechanical analysis, ultraviolet spectroscopy, scanning electron microscopy, wide‐angle X‐ray diffraction, thermogravimetric analysis, and tensile testing. The results indicated that the blend sheet with 80 wt % CMKGM exhibited good miscibility and higher tensile strength (89.1 MPa) than that of both WPU (3.2 MPa) and CMKGM (56.4 MPa) sheets. Moreover, with an increase of CMKGM content, the tensile strength, Young's modulus, and thermal stability increased significantly, attributed to intermolecular hydrogen bonding between CMKGM and WPU. Based on the experimental results, the blend materials have good, or a certain degree of, miscibility over the whole range of composition ratio of WPU to CMKGM. In addition, the blend materials exhibited organic solvent resistance. This work not only provided a simple method to prepare environmentally friendly materials, but also expanded the application of CMKGM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 77–83, 2004     

Application of crosslinked carboxymethyl konjac glucomannan in speciation of dissolved Fe(II) and Fe(III) in water samples

A new solid‐phase extraction technique has been developed for the speciation of trace dissolved Fe(II) and Fe(III) in environmental water samples with a microcolumn packed with crosslinked carboxymethyl konjac glucomannan (CCMKGM) prior to its determination by flame atomic absorption spectrometry (FAAS). Various influencing factors on the separation and preconcentration of Fe(II) and Fe(III), such as the acidity of the aqueous solution, sample flow rate and volume, and eluent concentration and volume, have been investigated systematically and optimized. Fe(III) could be quantitatively retained by CCMKGM in the pH range of 3.0–7.0, then the retained Fe(III) on the CCMKGM was eluted with 5.0 mol L^?1 HCl after cleaning with 0.01 mol L^?1 HCl to eliminate Fe(II) and determined by FAAS. Total Fe was determined after the oxidation of Fe(II) to Fe(III) by H₂O₂, and Fe(II) concentration was calculated by subtracting Fe(III) from total iron. The adsorption capacity of CCMKGM for Fe(III) was found to be as high as 162.3 mg g^?1. The detection limit (3σ) for Fe(III) was 1.5 μg L^?1 and the RSD was 3.5% (n = 11, c = 20 μg L^?1) with an enrichment factor of 50. The proposed method has been applied to the speciation of iron in water samples with satisfactory results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Blend films from chitosan and konjac glucomannan solutions

Blend films were prepared by blending 7 wt % konjac glucomannan (KGM) aqueous solution with 2 wt % chitosan (CH) in acetate solution and dried at 40°C for 4 h to obtain the transparent films. Their structure and properties were studied by infrared (IR), wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Crystallinities of the blend films decreased with the increase of konjac glucomannan. The thermostability, tensile strength, and breaking elongation of the blend films in dry state were obviously higher than those of both konjac glucomannan and chitosan films. Tensile strength of the dry blend film achieved 73.0MPa when the weight ratio of chitosan to konjac glucomannan was 7:3. The structure analysis indicated that there is a strong interaction between konjac glucomannan and chitosan resulted from intermolecular hydrogen bonds. The water solubility of the blend films was improved by blending with konjac glucomannan, so they have promising applications to soluble antiseptic coating of pills. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 509–515, 2000     

一种改性魔芋葡甘露聚糖的合成与表征

以三乙胺为催化剂,用没食子酸对魔芋葡甘露聚糖（KGM）进行酯化改性,反应条件为：m（KGM）∶m（三乙酰没食子酰氯）=1∶2,反应温度50℃,时间3 h,用饱和乙酸钠的无水乙醇溶液进行脱除乙酰基,得改性KGM,总收率为57.9%。     

Blend films from konjac glucomannan and sodium alginate solutions and their preservative effect

In order to enhance the mechanical properties of konjac glucomannan film in the dry state and research the application of konjac glucomannan on food preservation domain, blend transparent film was prepared by blending 3 wt % sodium alginate aqueous solution with 4.5 wt % konjac glucomannan aqueous solution and dried at 40^oC for 4 h. The structure and properties of the blend films were studied by infrared, wide angle X‐ray diffraction, scanning electron microscopy, and differential thermal analysis. Crystallinities of blend films were increased with the increase of sodium alginate. The tensile strength and breaking elongation of the blend films in dry state were obviously higher than those of both sodium alginate and konjac glucomannan films. Tensile strength of the dry blend film achieved 77.8 MP_a when the retention of sodium alginate in the film was 27.9 wt %. The structure analysis indicated that there was a strong interaction between konjac glucomannan and sodium alginate, and this is resulted from the intermolecular hydrogen bonds. Moisture content and degree of water swelling of the blend films were increased due to the introduction of sodium alginate. Results from the film coating preservation experiment to litchi and honey peach showed that this blend film had water‐holding ability. The fruit weight loss rate and rot rate both decreased by various values. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 617–626, 2000     

魔芋葡甘露聚糖的研究进展

综述了国内外对于魔芋葡甘露聚糖的结构、化学改性及应用的研究，提出了存在的问题，展望了发展前景。     

魔芋葡甘聚糖材料疏水改性的研究进展

介绍了魔芋葡甘聚糖与高分子材料共混疏水改性的方法,评述了化学改性中魔芋葡甘聚糖脱乙酰基化、交联、接枝共聚、互穿聚合物网络、羧甲基化等疏水改性的最新研究进展,探讨了其今后的研究方向,并提出了开发热塑性KGM材料这一前沿性课题。     

Preparation of konjac glucomannan ester of palmitic acid and its emulsification

Various degrees of palmitoylated konjac glucomannan (PKGM) are prepared by a heterogeneous method. Differential thermal analysis thermographs show PKGM having 0.51 degrees of substitution (DS) gave a new crystalline peak at higher temperature. With the increase of DS, the former crystalline state of konjac glucomannan will disappear; PKGM only shows the new crystalline state. Furthermore, the effect of the DS of PKGM on its emulsifying ability has been investigated in the water in oil and oil in water systems. It is demonstrated that it is a kind of good water in oil emulsifier, with the DS ranged between 1.00 and 1.70, whereas DS < 0.50. It is a kind of good oil in water emulsifier and an interesting phenomenon appears in the water in oil system. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1035–1038, 1998     

魔芋葡甘聚糖复合凝胶的制备及其溶胀性能研究

通过在水中复配魔芋葡甘聚糖(KGM)、黄原胶(XG)和β-环糊精(β-CD),制备了KGM/XG/β-CD复合水凝胶。探讨了β-CD含量对凝胶平衡溶胀度的影响,并探讨了介质pH和温度对凝胶溶胀度的影响。结果表明,当m(KGM):m(XG):m(β-CD)=1:1:1时,复合凝胶的平衡溶胀度最大;复合凝胶的溶胀度在溶胀初期增加很快,随着溶胀时间的延长,溶胀度增加变慢,约7 h内基本达到平衡;随着介质pH的增大或体系温度从25℃增加至37℃,KGM/XG/β-CD复合凝胶的溶胀度随之增大。     

魔芋葡甘聚糖及其衍生物的应用研究进展

综述了魔芋葡甘聚糖(KGM)及其衍生物在食品、医药及环保等领域的应用,表明KGM具有较高的学术研究价值及广阔的应用前景。     

Synthesis and characterization of konjac glucomannan/poly(vinyl alcohol) interpenetrating polymer networks

Novel interpenetrating polymer networks (IPNs) coded as KP were synthesized successfully from poly(vinyl alcohol) (PVA) and konjac glucomannan (KGM) in the presence of glutaraldehyde as a crosslink agent. The transparent IPN films that were 40 μm thick were prepared by means of conventional solvent‐casting technique and dried at room temperature for 2 days. The structure and miscibility of the KP films were studied by Fourier transformed infrared spectra, scanning electron microscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, and ultraviolet visible spectroscopy (UV–Vis). The results indicated that strong intermolecular interaction caused by crosslink bonding between PVA and KGM occurred in the IPN films, resulting in wonderful miscibility when the reaction time is 4 h. The tensile strength, elongation at break, and moisture uptake was much higher than that of the pure PVA film, KGM film, and uncrosslinked blend films. In other words, the structure of IPN endowed the films with excellent performance, so the new material has promising applications to food package film and agricultural film because of its biodegradability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2775–2780, 2004     

具有吸水保水功能的改性魔芋共聚物包膜缓释尿素的制备及其性能研究

以烯丙基硫脲改性魔芋葡甘聚糖为包膜剂制备包膜缓释尿素。对包膜缓释材料进行扫描电子显微镜(SEM)表征,并分析其吸水性能;评价温度及土壤水含量对包膜缓释尿素氮素溶出率的影响,利用土柱淋溶法检测包膜缓释尿素的缓释效果,并分析缓释尿素对白菜的生长影响。结果表明,烯丙基硫脲接枝魔芋葡甘聚糖在接枝率为35%~45%时,吸水性能最好,吸水量高达794 g/g;随着温度和土壤水含量的升高,包膜缓释尿素氮素溶出率逐渐增加;氮素溶出具有典型的缓释肥溶出特征,表现出良好的缓释效果;白菜对缓释尿素中氮素的利用率提高。     

Study on properties and aggregation structures of deacetylated konjac glucomannan/chitosan hydrochloride absorbent blend gel films

A series of novel blend films of deacetylated konjac glucomannan (d‐KGM) and Chitosan hydrochloride (CHI·HCl) were prepared successfully by using the solvent‐casting technique with different blending ratios of the two polymers. The miscibility and aggregation structure of the blend films were studied by Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction and scanning electron microscopy. The results indicated that the blend system of d‐KGM and CHI·HCl had a conditional miscibility. A new crystal occurred and hydrogen‐bonding interaction was strengthened when the CHI·HCl content in the blend films was 40%. The effects of deacetylation degree of KGM, acids (the solvent Chitosan dissolved in), temperature, and the mix ratio on the swelling behavior of the blend films were also studied. The blend film KC3 (CHI·HCl content in the blend films was 30%) had not only the highest equilibrium swelling degree (26 times) but also the highest tensile strength, and it could be regarded as a potential absorbent film material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

羧甲基纤维素钠/凹凸棒石纳米复合材料的制备与表征

以羧甲基纤维素钠(CMC-Na)为基体,凹凸棒石(AT)为增强材料,采用溶液共混法制备了标题物。研究了凹凸棒石用量对纳米复合材料结构和性能的影响。通过FT-IR、TG、SEM对复合材料进行了表征。试验结果表明,当凹凸棒石用量为羧甲基纤维素钠质量的0.22%时,复合材料的力学性能最佳。由于纳米凹凸棒石的引入,CMC-Na分子某些特征峰的波数发生了变化,复合材料的形貌也发生了改变;羧甲基纤维素钠/凹凸棒石纳米复合材料的热稳定性高于纯羧甲基纤维素钠膜。     

Lipase‐catalyzed acylation of konjac glucomannan in ionic liquids

A comparative study was made of lipase‐catalyzed acylation of konjac glucomannan (KGM) with vinyl acetate as the acyl donor in five ionic liquids (ILs) and also in the presence of the organic solvent tert‐butanol (t‐BuOH). An obvious enhancement in enzyme activity and stability was observed using ILs as the reaction media when compared with t‐BuOH. The maximum degree of substitution (DS) of the modified KGM in ILs and t‐BuOH under the conditions employed is 0.71 and 0.54, respectively. The water activity (a_w) of the reaction system affected the acylation of KGM to some extent. 1‐Butyl‐3‐methylimidazolium tetrafluoroborate (C₄MIm.BF₄) was the best IL medium for the reaction, and an a_w of 0.75 was optimum. It was also found that the nature of both the cation and the anion of ILs had an effect on the reaction. Candida antarctica lipase B immobilized on an acrylic resin (Novozym 435) displayed no acylation activity to KGM in 1‐butyl‐3‐methylimidazolium chloride (C₄MIm.Cl). The optimum reaction temperature for enzymatic acylation in ILs was shown to be 45‐55 °C. Enzymatic acylation of KGM in IL‐t‐BuOH co‐solvent systems was also investigated. When an appropriate amount of t‐BuOH was added to ILs, the DS of the modified KGM was enhanced. Additionally, the enzymatic acylation of KGM in all the media examined was shown to be regioselective, with acylation occurring predominantly at the C‐6‐OH. Copyright © 2006 Society of Chemical Industry     

魔芋粉-丙烯酸-丙烯酰胺接枝共聚合成高吸水树脂

以魔芋粉,丙烯酸和丙烯酰胺等为原料,经接枝聚合合成了魔芋粉－丙烯酸－丙烯酰胺类超强吸水性树脂。讨论了引发剂,交联剂,丙烯酸,丙烯酰胺等用量以及反应时间和反应温度等因素对树脂吸水性能的影响。结果表明: 在魔芋粉与单体质量比为1:4,引发剂用量为0.35%（占单体的质量）,丙烯酸/丙烯酰胺（质量）为1:1,丙烯酸中和度为80% ,反应温度为55～65℃,交联剂用量为0.75%（占单体的质量）的条件下,制得的SAP吸去离子水可达720g/g,吸0.9%的NaCl溶液为110g/g。