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Dielectric spectroscopic studies of biological material evolution and application to paper, TAPPI JOURNAL September 2018
Dielectric spectroscopic studies of biological material evolution and application to paper, TAPPI JOURNAL September 2018
Journal articles
Magazine articles
Progress in foam forming technology, TAPPI JOURNAL August 2019
ABSTRACT: This paper summarizes recent developments in foam forming that were mainly carried out in pilot scale. In addition to improving the efficiency of existing processes and allowing better uniformity in material, a wide variety of raw materials can be utilized in foam forming. The focus of this paper is thin webs—papers, boards and foam-laid nonwovens, along with the pilot scale results obtained at VTT in Finland. For paper and board grades, the most direct advantage of foam forming is the potential to produce very uniform webs from longer and coarser fibers and obtain material savings through that. Another main point is increased solids content after a wet press, which may lead to significant energy savings in thermal drying. Finally, the potential to introduce “difficult” raw materials like long synthetic or manmade fibers into a papermaking process enables the manufacturing of novel products in an existing production line. This paper also briefly discusses other interesting foam-based applications, including insulation and absorbing materials, foam-laid nonwovens, and materials for replacing plastics.
Journal articles
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Effects of different ammonium lignosulfonate contents on the crystallization, rheological behaviors, and thermal and mechanical properties of ethylene propylene diene monomer/polypropylene/ammonium lignosulfonate composites, TAPPI Journal January 2020
ABSTRACT: Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has an excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the AL contents on the crystallization behaviors, rheological properties, thermal properties, and mechanical properties of the composites. The results showed that the AL content had a noticeable impact on the performance of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.
Journal articles
Magazine articles
Guest Editorial: Coating research addresses new product demands in response to global pandemic, TAPPI Journal November 2020
ABSTRACT: For all of us, the year 2020 has been one of significant challenge. Our communities, companies, institutions, organizations, and families have had to make many tough decisions and change our way of life as a result of the global pandemic.
Journal articles
Magazine articles
Discrete element method to predict coating failure mechanisms, TAPPI JOURNAL January 2018
Discrete element method to predict coating failure mechanisms, TAPPI JOURNAL January 2018
Journal articles
Magazine articles
Factors affecting the free shrinkage of handsheets: apparent density, fines content, water retention value, and grammage, TAPPI JOURNAL June 2018
Factors affecting the free shrinkage of handsheets: apparent density, fines content, water retention value, and grammage, TAPPI JOURNAL June 2018
Journal articles
Magazine articles
Predicting strength characteristics of paper in real time using process parameters, TAPPI Journal March 2022
ABSTRACT: Online paper strength testing methods are currently unavailable, and papermakers have to wait for manufacture of a complete reel to assess quality. The current methodology is to test a very small sample of data (less than 0.005%) of the reel to confirm that the paper meets the specifications. This paper attempts to predict paper properties on a running paper machine so that papermakers can see the test values predicted in real time while changing various process parameters. This study was conducted at a recycled containerboard mill in Chicago using the multivariate analysis method. The program provided by Braincube was used to identify all parameters that affect strength characteristics. Nearly 1600 parameters were analyzed using a regression model to identify the major parameters that can help to predict sheet strength characteristics. The coefficients from the regression model were used with real-time data to predict sheet strength characteristics. Comparing the prediction with test results showed good correlation (95% in some cases). The process parameters identified related well to the papermaking process, thereby validating the model. If this method is used, it may be possible to predict various elastic moduli (E11, E12, E22, etc.) in the future as the next step, rather than the traditional single number “strength” tests used in the containerboard industry, such as ring crush test (RCT), corrugating medium test (CMT), and short-span compression strength test.
Journal articles
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Impact of different calendering strategies on barrier coating pickup, TAPPI Journal November 2023
ABSTRACT: Paper was pre-calendered in a pilot scale configuration with a traditional soft nip calender and a metal belt calender. All calendering strategies reduced surface roughness and permeability of the samples, but different strategies affected the surface roughness and permeability differently. The metal belt calender seemed to have a larger effect on the large-scale variations compared to the soft nip calender. Six test points from the pilot calendered papers were chosen for laboratory coating studies. Uncalendered paper was included as reference samples. The calendered samples and the reference were pre-coated with a regular pigmented coating consisting of a ground calcium carbonate (GCC) pigment and a styrene acrylate (SA) latex. Both uncoated and pre-coated substrates were barrier coated with a polyvinyl alcohol (PVOH) in one and two layers. The coating pickup was determined gravimetrically, and the barrier properties were evaluated with TAPPI Standard Test Method T 454 grease resistance test. All samples needed two PVOH coating layers to form a grease barrier. The uncalendered sheets showed the best results with one coating layer, but this was at the expense of a higher coating pickup compared to the calendered sheets. The barrier coating pickup could be reduced by a combination of high temperature metal belt calendering and pre-coating. The high temperature and long residence time in the nip enabled plasticization of the fibers. This led to an irreversible deformation, even after water application. This meant that the smoothness obtained during calendering would be less affected by water-induced roughening during the coating operation.
Journal articles
Magazine articles
Use of kaolin clay in aqueous barrier coating applications, TAPPI Journal November 2023
ABSTRACT: Paper-based packaging with barrier effect, as opposed to single use plastics, is gaining more prominence for sustainability reasons. At the same time, latex- or biopolymer-based aqueous barrier coating dispersions are increasingly being adopted as a better alternative to the traditional barrier coating materials, such as wax, surface active chemicals, and polyethylene. In this work, studies were performed to determine the influence of different kaolin clays in latex binder-based aqueous coatings on barrier properties, namely, oil and grease, water resistance, and water vapor transmission rate, by applying coatings to solid bleached sulfate (SBS) paperboard substrate in the laboratory. The aim was to explore potential benefits of using kaolin clay to replace some of the latex binder in coating and improve or maintain various types of barrier performance and blocking without negatively influencing the other performance attributes, including heat seal. The delaminated clay with the highest shape factor provided improved barrier properties over the clays of low shape factor. The ultrafine and non-delaminated clays required significantly higher coat weights to reach satisfactory barrier properties. Coatings with different latex levels indicated that a considerably high proportion of coarse delaminated clay can be incorporated to replace latex binder, while still achieving exceptional barrier properties. Furthermore, a change in binder system was found to significantly alter the barrier properties and the role that a mineral pigment can play. The results indicate that a proper selection of binder systems for each barrier property would be required while considering the clay/latex coating systems.
Journal articles
Magazine articles
A true green cover for industrial waste landfills, TAPPI Journal April 2024
ABSTRACT: Greenhouse gas (GHG) emissions in the United States totaled 5,981 million metric tons of carbon dioxide equivalent (MMT CO2eq) in 2020. Of that, GHG emissions by the pulp and paper sector amounted to 35 MMT CO2eq direct emissions and those by industrial waste landfills summed to 7.4 MMT CO2eq direct emissions. Loss of GHG sinks due to change in land use further contributes to the net GHG emissions. Industrial waste landfills are typically required to comply with certain federal and state regulations, including meeting requirements for final cover systems. Conventional final cover systems have included use of soil covers and/or soil-geosynthetic composite covers. An engineered turf cover provides for an excellent “green” alternative final cover system for industrial waste landfills.This paper discusses various sustainability aspects pertaining to use of an engineered turf final cover, including: (i)significantly low carbon footprint associated with the construction of an engineered turf alternative final coverwhen compared to closure using a traditional or prescriptive cover system; (ii) saving valuable soil and land resourc-es; (iii) saving water resources by reduction in its use during and after construction; (iv) reducing impacts associated with borrow areas; and (v) reducing overall carbon footprint. Further, when using an engineered turf cover, opportunities exist for beneficial reuse of land, including development of solar energy. A brief discussion on the potential fordevelopment of solar energy is included.