Preparation Of Carboxymethyl Hydroxyethyl Guar Gum And Its Application In Papermaking

With increasingly serious environmental pollution in recently, guar gum as a natural polymer obtained people’s favor, because of its rich source of non-toxic and environmentally friendly. Guar gum structure is similar to cellulose and it is easy by chemical modification, which makes it become a very potential new environmentally friendly auxiliaries. In this paper, synthesis and characterization of carboxymethyl hydroxyethyl guar aum(CMHEG) were studied. Moreover, the performance of strengthening, retention and drainage of CMHEG was investigated in papermakingBased on guar gum original powder, sodium chloride ethanol, chloroacetic acid and sodium hydroxide, in ethanol- water two phase reaction system, CMHEG has been synthesized by one step method. By optimizing the reaction conditions, it is found that when dosage of ethanol chlorine is 10 m L, dosage of sodium chloroacetate is 10 g, dosage of sodium hydroxide is 5g, reaction time is 8h, can obtain a higher degree of substitution, at this time CMHEG’s molar substitution degree is 0.28, carboxymethyl substitution degree is 0.34.The infrared spectrum of the product indicated that guar gum original powder is successfully introduced the hydroxyethyl carboxymethyl and nuclear magnetic resonance hydrogen spectrum shows that CMHEG samples in semi lactose and mannose content ratio of about 1: 1.25. By integrating the peak area calculated that CMHEG’s carboxymethyl degree of substitution is 0.242, hydroxyethyl molar substitution is 0.124, the result of the measurement value and pickling, chromatography are basically the same, mutually confirm the accuracy of several test methods. The differential scanning calorimetry shows that CMHEG is better than the original powder. For the solubility, CMHEG is more soluble than the original powder, the hydration rate is faster. Rheological test results show that CMHEG solution is a typical pseudo plastic fluid, with good shear thinning properties, and pH is stable in the range of 5~9.For CMHEG this green papermaking additives, it has been found to improve the paper tensile, tear and burst index, when the dosage was 0.6%, compared to the base paper tensile index increased by 21.3%, burst index increased by 38.1%, tear index increased 22.2%. CMHEG on the paper material retention is also effective. With the increase of CMHEG, paper material and the total retention rate showed an upward trend, drainage performance also improved. When the dosage was 0.6%, compared with no addition CMHEG, paper material and the total retention rate is increased by 10.3%, beating degree decreased the 2.4 oSR. Guar original powder showing yellow, and adding it in the wet end of papermaking does not help to improve the brightness of paper. However, the modified CMHEG is a white or slightly yellow powder, add brightness of the paper will have some impact, but little. For brightness itself is less than CMHEG pulp, even though add CMHEG can improve the brightness of the paper.In the study CMHEG paper applications, while also boosting the mechanism to do some preliminary study. By measuring the variation of mechanical and optical properties before and after CMHEG added paper, with the use of FTIR, SEM and other analytical tools, combined with the relative area of the paper, chemical bond between the fibers of the analyzes found that CMHEG amount of from 0 to 1 percent, the paper tensile index improved from 21.6N · m / g to 26.5N · m / g, relative binding area increased from 32% to 41%. Scanning electron microscope images showed that CMHEG improved the cross-linking of fibers, which lead to the fracture surface of the sheet is mainly consisting of broken fibers and the slip between fibers is strengthened. The results of IR spectra indicated that there was no covalent bond between fibers and additive. Further experiments demonstrated that the addition of CMHEG enhanced the strength of the sheet through the increase of bonding interaction and the bonded area between fibers. The bonding interaction resulting in the enhanced strength of the sheet is mainly intermolecular hydrogen bonding between fibers. In addition, van der Waals force also contributes to bonding interactions to some degree.