scholarly journals Preparation of Lignin-Based High-Ortho Thermoplastic Phenolic Resins and Fibers

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3993
Author(s):  
Yu Ren ◽  
Jin Xie ◽  
Xiahong He ◽  
Rui Shi ◽  
Can Liu
Keyword(s):  
Molecular Weight ◽  
Melt Spinning ◽  
Phenolic Resin ◽  
Economic Value ◽  
P Value ◽  
Phenolic Resins ◽  
Elongation At Break ◽  
Application Field ◽  
Before And After ◽  
Forestry Industry

Surplus lignin, which is inefficiently used, is generated in the forestry industry. Currently, most studies use lignin instead of phenol to synthesize thermosetting resins which cannot be reprocessed, thus affecting its application field. Thermoplastic phenolic resin has an orderly structure and excellent molding performance, which can greatly improve its application field and economic value. Herein, phenol was partially replaced with enzymolysis lignin (without treatment), generating lignin-based high-ortho thermoplastic phenolic resins (LPRs), and then lignin-based phenolic fibers (LPFs) were prepared by melt spinning. FTIR, 13C-NMR and GPC were used to characterize the ortho–para position ratio (O/P value), molecular weight and its distribution (PDI), and rheological properties of the resin. TG, XRD, SEM and tensile property studies were used to determine the thermal stability, orientation, and surface morphology of the fiber. Lignin addition resulted in the decline of the O/P value and molecular weight of the resin. For the 10% LPR, the O/P value, Mw, and PDI were 1.28, 4263, and 2.74, respectively, with the fiber exhibiting relatively good spinnability. The tensile strength and elongation at break of the 10% LPF were 160.9 MPa and 1.9%, respectively. The addition of lignin effectively improved the thermal properties of the fiber, and the carbon yields of 20% LPF before and after curing were 39.7% and 53.6%, respectively, which were 22.2% and 13.7% higher than that of the unmodified fiber, respectively.

Improving the Thermal and Mechanical Properties of Phenolic Fiber over Boron Modified High-Ortho Phenolic Resin

2020 ◽  
pp. 095400832097675
Author(s):  
Yu Ren ◽  
Xu Lin ◽  
Zhengjun Shi ◽  
Yunwu Zheng ◽  
Jianxiang Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Boric Acid ◽  
Melt Spinning ◽  
Phenolic Resin ◽  
Raw Materials ◽  
Fiber Strength ◽  
Average Molecular Weight ◽  
P Value

Boron-modified high-ortho phenolic resins (BPRs) were prepared under normal pressure by using phenol and formaldehyde as raw materials, zinc acetate, and oxalic acid as catalysts, and boric acid as a modifier. Boron-modified phenolic fibers (BPFs) were prepared by melt spinning and curing in a mixture of formaldehyde and hydrochloric acid, followed by a heat treatment under high temperature. The structure, ortho–para ratio (O/P), molecular weight and distribution, spinnability, thermal stability, fiber strength, and morphology of the resins were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and fiber strength testing. The results showed that the addition of boric acid reduced the ortho reaction of the synthetic resin and the O/P value of phenolic resin. When the content of boric acid was 3 wt%, the thermal stability was the best, the O/P value was up to 3.26, and the weight average molecular weight (Mw) was 18745 g/mol. In Compared with the unmodified resin, the mass loss was increased by 33.7%, and finally the carbon yield was 51.2%. The tensile strength of the fibers reached 187.2 MPa and the elongation at break was 10.5%. By introducing boron into the molecular chain, the structure of the resin was improved, and the thermal stability and mechanical properties of the fibers were improved.

The Effect of Triacetin on the Plasticization Efficiency and Tensile Properties of Polyvinyl Chloride/di-2-Ethyl Hexyl Phthalate/Triacetin Compounds

2016 ◽  
Vol 1133 ◽  
pp. 206-210 ◽  
Author(s):  
Arjulizan Rusli ◽  
Nur Farhana Asul Kahar
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Glass Transition ◽  
Tensile Properties ◽  
Polyvinyl Chloride ◽  
Chemical Structure ◽  
Low Molecular Weight ◽  
Migration Ability ◽  
Elongation At Break ◽  
Before And After

The use of triacetin as an alternative plasticizer to polyvinyl chloride (PVC) was studied in term of plasticizer efficiency and tensile properties before and after ageing. The efficiency of plasticizers was evaluated based on the glass transition temperature (Tg) and the hardness value of the compounds. The Tg and hardness of all PVC/DEHP/Triacetin compounds are lower than PVC/50DEHP and PVC/50Triacetin compounds indicating synergistic plasticisation effect between both DEHP and Triacetin within the PVC compounds. The low molecular weight and chemical structure of triacetin are believed to contribute to the highest tensile strength, elongation at break and modulus of the PVC/triacetin compared with PVC/DEHP and PVC/DEHP/triacetin compounds. However, the migration ability of the triacetin plasticizer is believed to result in the biggest changes of the tensile properties of PVC compounds plasticized with triacetin before and after ageing.

Pengaruh Perawatan Metode Kanguru (PMK) terhadap Pencegahan Hipotermi pada Bayi Baru Lahir

2020 ◽  
Vol 2 (2) ◽  
pp. 66-71
Author(s):  
Parti ◽  
Sumiati Malik ◽  
Nurhayati
Keyword(s):  
Birth Weight ◽  
Infant Mortality ◽  
Low Birth Weight ◽  
Health Workers ◽  
Kangaroo Mother Care ◽  
Infant Mortality Rate ◽  
P Value ◽  
Low Birth Weight Infants ◽  
Low Birth Weight Babies ◽  
Before And After

Most causes of infant death are problems that occur in newborn/neonatal (0-28 days old), Low Birth Weight Babies (LBW) is one of the factors which has a contribution to infant mortality, especially in the neonatal period. Infant Mortality Rate (IMR) is a benchmark in determining the degree of public health, both at the National and Provincial levels. This study aimed to determine the effect of the Kangaroo Mother Care Method (KMC) on the prevention of hypothermia in low birth weight infants at Morowali District Hospital in 2019. The type of research used was a quasi-experiment. The population is all low birth weight babies born from May to July 2019. The sample in this study was all newborns with low birth weight born from May to July 2019, totaling 30 babies. There is a difference (influence) on the baby's body temperature before and after KMC with a p-value=0,000. The kangaroo mother care can continue to be affiliated considering its benefits for both infants and mothers, as well as increasing the ability of health workers in conducting KMC so that they can provide in-house training for mothers to be carried out at home.

PENGARUH PIJAT BAYI TERHADAP KUALITAS TIDUR BAYI UMUR 0 – 3 BULAN DI WILAYAH KERJA PUSKESMAS SOSIAL PALEMBANG TAHUN 2016

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Juliana Widyastuti Wahyuningsih Juliana Widyastuti Wahyuningsih
Keyword(s):  
Experimental Design ◽  
Growth And Development ◽  
Sampling Technique ◽  
P Value ◽  
Development Phase ◽  
Quality Of Sleep ◽  
Infant Massage ◽  
Before And After ◽  
The Brain

ABSTRAK Tidur merupakan kebutuhan yang harus terpenuhi terutama pada fase perkembangan karena selama tidur akan terjadi perkembangan otak maupun tubuh, sehingga gangguan tidur merupakan masalah yang akan menimbulkan dampak buruk terhadap pertumbuhan dan perkembangan bayi. Kualitas tidur bayi yang baik dapat diciptakan dengan memberikan pemijatan bayi secara rutin. Penelitian ini bertujuan untuk membuktikan bahwa pemijatan dapat mempengaruhi kualitas tidur bayi umur 0-3 bulan. Penelitian ini menggunakan desain penelitian Quasy Eksperimental dengan metode One Group Pretest-Postest. Sampel 22 bayi yang dipilih dengan tehnik Total Sampling yang di observasi sebelum dan sesudah diberikan pemijatan. Variabel yang diukur dalam penelitian ini adalah kualitas tidur bayi 0-3 bulan. Hasil penelitian menunjukkan bahwa ada pengaruh pijat bayi terhadap kualitas tidur bayi umur 0-3 bulan (p value  0,008 < α = 0,05).Berdasarkan hasil penelitian ini disarankan agar keluarga dan masyarakat memberikan pemijatan secara rutin dan mandiri untuk meningkatkan kebutuhan tidur bayi yang berkualitas.   ABSTRACT Sleep is a human necessity that must be met, especially in the development phase because during sleep will occur the brain and body developments, so that sleep disturbance is a problem that would cause adverse effects on infants’ growth and development. The good quality of sleep can be created by providing the infants massage routinely. This study aimed to prove that the massage could affect the quality of sleep on the 0-3 months old baby. This study used Quasy-experimental design with One Group Pretest-Posttest. The sample 22 infants selected by total sampling technique observed on before and after the massage. The variables measured in this study are the quality of sleep. The results of study indicate that there is an effect of infant massage to the sleep quality on 0-3 months old babies (p value 0,008 < α = 0,05).Based on the results of this study it recommended for the families and communities to provide infant massage regularly and independently to increase the quality of sleep on the baby.  

Porous Structure and Transport Properties of a Carbonized Phenolic Resin

1995 ◽  
Vol 60 (2) ◽  
pp. 172-187 ◽  
Author(s):  
Pavel Fott ◽  
František Kolář ◽  
Zuzana Weishauptová
Keyword(s):  
Porous Structure ◽  
Transport Properties ◽  
Phenolic Resin ◽  
Arrhenius Equation ◽  
Mercury Porosimetry ◽  
Micropore Volume ◽  
Microporous Structure ◽  
Wetting And Drying ◽  
Phenolic Resins ◽  
Kinetics Of

On carbonizing phenolic resins, the development of porous structure takes place which influences the transport properties of carbonized materials. To give a true picture of this effect, specimens in the shape of plates were prepared and carbonized at various temperatures. The carbonizates obtained were studied by adsorption methods, electron microscopy, and mercury porosimetry. Diffusivities were evaluated in terms of measuring the kinetics of wetting and drying. It was found out that the porous structure of specimens in different stages of carbonization is formed mostly by micropores whose volumes were within 0.06 to 0.22 cm3/g. The maximum micropore volume is reached at the temperature of 750 °C. The dependence of diffusivity on the carbonization temperature is nearly constant at first, begins to increase in the vicinity of 400 °C, and at 600 °C attains its maximum. The experimental results reached are in agreement with the conception of the development and gradual closing of the microporous structure in the course of carbonization. The dependence of diffusivity on temperature can be expressed by the Arrhenius equation. In this connection, two possible models of mass transport were discussed.

Olfactory Training Using Heavy and Light Weight Molecule Odors

Perception ◽  
2016 ◽  
Vol 46 (3-4) ◽  
pp. 343-351 ◽  
Author(s):  
Sophia C. Poletti ◽  
Elisabeth Michel ◽  
Thomas Hummel
Keyword(s):  
Molecular Weight ◽  
Olfactory Dysfunction ◽  
Light Weight ◽  
Short Term ◽  
Olfactory Loss ◽  
Short Term Exposure ◽  
Before And After ◽  
Phenyl Ethyl Alcohol ◽  
A Prospective Study ◽  
Olfactory Training

Background Repeated short-term exposure to odors is known to improve olfaction in patients with acquired olfactory dysfunction. The aim was to find out whether differences in molecular weight of odors used for olfactory training influences olfaction. We hypothesized a greater improvement following training with light weight molecule (LWM) odors. Methods A prospective study was performed in patients with posttraumatic (PTOL) and postviral olfactory loss (PVOL). Olfactory training was performed over a period of 5 months. One group ( n = 48) used four odors containing heavy weight molecules (HWM; >150 g/mol) and another ( n = 48) containing LWM (<150 g/mol). Olfaction was tested before and after the training using the Sniffin’ Sticks test. Results Olfactory training was associated with olfactory improvement, with the improvement in PVOL patients being three times greater than that seen in the PTOL group. Compared with LWM training, HWM training was associated with a significantly greater improvement in Phenyl Ethyl Alcohol (PEA) threshold scores in PVOL patients; however, no such improvement could be shown for other subtests or in PTOL patients. Conclusion Overall, training was associated with olfactory improvement. With the exception of threshold scores in PVOL, there were no significant differences between LWM and HWM groups.

High-Speed Melt Spinning of Sheath-Core Bicomponent Polyester Fibers: High and Low Molecular Weight Poly(ethylene Terephthalate) Systems

1997 ◽  
Vol 67 (9) ◽  
pp. 684-694 ◽  
Author(s):  
J. Radhakrishnan ◽  
Takeshi Kikutani ◽  
Norimasa Okui
Keyword(s):  
Molecular Weight ◽  
High Speed ◽  
Melt Spinning ◽  
Ethylene Terephthalate ◽  
Maxwell Model ◽  
Low Molecular Weight ◽  
Structural Development ◽  
Solidification Temperature ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Sheath-core bicomponent spinning of high molecular weight poly (ethylene terephthalate) (hmpet, IV = 1.02 dl/g) and low molecular weight pet (lmpet, IV = 0.65 dl/g) is done at a take-up velocity range of 1 to 7 km/min. The structures of the individual components in the as-spun bicomponent fibers are characterized. Orientation and orientation-induced crystallization of the hmpet component are enhanced, while those of the lmpet component are suppressed in comparison to corresponding single component spinning. Numerical simulation with the Newtonian model shows that elongational stress in the hmpet component is enhanced and that of the lmpet decreases during high-speed bicomponent spinning. The difference in elongational viscosity is the main factor influencing the mutual interaction between hmpet and lmpet, which in turn affect spinline dynamics, solidification temperature, and structural development in high-speed bicomponent spinning. Simulation with an upper-convected Maxwell model shows that considerable stress relaxation can occur in the lmpet component if the hmpet component solidifies before lmpet. A mechanism for structural development is also proposed, based on the simulation results and structural characterization data.

Research on In Situ Anionic Polymerization of PA6/PI Alloy

2011 ◽  
Vol 295-297 ◽  
pp. 21-25
Author(s):  
Hong Kai Zhao ◽  
Li Guang Xiao ◽  
Hong Jie Wang
Keyword(s):  
Molecular Weight ◽  
Bisphenol A ◽  
High Performance ◽  
Hot Spot ◽  
Microscopic Analysis ◽  
Infrared Analysis ◽  
Elongation At Break ◽  
System Temperature ◽  
Lamellar Crystals

High performance trend of plastics has become a hot spot of current research. Select bisphenol A dianhydride and bisphenol A diamine with excellent water resistance as the reactant monomers to obtain anhydride-terminated polyimide with very high molecular weight by two-step polymerization, graft the active radicals of acyl caprolactam using the activity of anhydride and obtain PI modified nylon resin by polymerization.When the system temperature is above 160 °C and the added modifiers are greater than 10%, the system viscosity increases very fast; when the system temperature reaches 140 °C and the added modifiers are at 5%, the system viscosity increases very slowly. It is proved that the reaction in each above step is successful through infrared analysis. The mechanical properties of modified PI nylon increases with the increase of consumption and molecular weight of polyimide, when the molecular weight is selected to be about 8000~10000 and the adding amount is 10wt%~15 wt%, the tensile strength reaches over 85MPa, the notch impact strength is increased to 19.6kJ.m-2 and the elongation at break reaches 18%, which are remarkably better than general engineering plastics.Through microscopic analysis, the molecules of polyimide does not enter crystallization phase of nylon resin, but forms compact lamellar crystals existing in nylon matrix.

Phototherapy Induced Hypocalcemia in Neonates with Unconjugated Hyperbilirubinemia

2021 ◽  
Vol 11 (1) ◽  
pp. 4-8
Author(s):  
Amna Khan ◽  
Anila Farhat ◽  
Hamayun Anwar ◽  
Sajid Shamim ◽  
Mujeeb Ur Rehman ◽  
...  
Keyword(s):  
Serum Calcium ◽  
Calcium Level ◽  
Serum Calcium Level ◽  
Neonatal Intensive Care ◽  
Cross Sectional Study ◽  
Categorical Variables ◽  
P Value ◽  
Cross Sectional ◽  
Unconjugated Hyperbilirubinemia ◽  
Before And After

Objective: To determine the frequency of hypocalcemia in neonates with unconjugated hyperbilirubinemia receivingphototherapy.Study design and setting: Cross sectional study conducted at neonatal intensive care unit, King Abdullah Teaching Hospital,Mansehra for one year from December 2017 to November 2018.Methodology: Total 213 full term stable neonates of either gender with jaundice were studied in this study. Out of which,143 with unconjugated hyperbilirubinemia were exposed to phototherapy while 70 neonates with exaggerated physiologicalhyperbilirubinemia taken as control were not exposed to phototherapy. Serum calcium level was determined through bloodtest before and after 24 hours of phototherapy. SPSS version 22 was used to analyze the data. Frequency and percentageswere used to describe categorical variables like gender and hypocalcemia. Hypocalcemia was stratified by age and genderto see effect modifiers. Post stratified chi-square test was applied in which p value = 0.05 was considered as significancevalue.Results: In study group, 143 neonates who received phototherapy had mean age of 7 days ± 2.62 SD. Total 65% neonateswere male and 35% neonates were female. Mean serum calcium level of neonates before and after provision of phototherapywas 9.28 mg/dl ± 0.23 and 8.54 mg/dl ± 0.68 respectively, which is statistically significant. The frequency of hypocalcemiawas 40% in neonates with unconjugated hyperbilirubinemia after 24 hours of phototherapy.Conclusion: Hypocalcemia is an important complication in neonates with unconjugated hyperbilirubinemia after continuousphototherapy. Hypocalcemia has clinical impact and adds to morbidity, and if left untreated, can lead to mortality.

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