Research Opportunities in Wet-End
Research opportunities
Graduate studies   Click on "Graduate studies" or scoll down to the section below if you want to get a Masters or Ph.D. degree and have an interest in papermaking chemistry.
Corporate partners   Click on "Corporate partners" if you represent a company that has critical needs in papermaking chemistry that could be met through research projects at a university.
Emerging technology   Click on "Emerging technology" to get a quick overview about results of recent research at NCSU related to papermaking chemistry.

Graduate Study & Research Opportunities: Graduate studies

The GRADUATE SCHOOL at NC State University has a site giving complete, updated information about opportunities to get Masters and Ph.D. degrees. The site tells about what you need in order to quality, how to apply, and what to expect from the program. For example, the site tells about such things as GRE requirements, letters of reference, transcripts, and TOEFL test requirements for students whose primary language is not English. Further official information is provided in the site maintained by the Department of Wood and Paper Science.

As we see it, there are basically two reasons why people undertake graduate research projects.
1. They want to advance in their present of future careers.
2. They enjoy the challenge and satisfaction of excelling in their field and producing new knowledge.

Both these goals - career advancement, as well as satisfaction - depend on the quality and reputation of the program. They also depend on achieving a good fit between the student's interests and potential research interests and current projects in the department.

If you are interested in doing research in papermaking chemistry, then please also send an E-Mail. We appreciate learning that other people are interested in this area of science. We would be glad to here from you and to answer your questions about what we are doing recently at NC State and how it might relate to your interests.


Each year, throughout the year, the Department of Wood and Paper Science is engaged in a process of seeking highly qualified students for its graduate program. Departmental grants are awarded to incoming students on a competitive basis to cover tuition, health insurance, and living expenses during the freshman year. In subsequent semesters the typical student is supported by specific research grants. These specific grants are related to the research work being carried out by that student.

Areas of Research Interest

The nature of some current wet-end chemical projects at NCSU are described in more detail elsewhere in this website. After you leave this section you might want to explore the bottom section on this page ("Emerging technologies").

To summarize, some areas of research where we continually need to recruit new candidate M.S. and Ph.D. students are as follows:

Research Projects in Wet-End Chemistry

I would like to hear from you if you have finished reading through the list above, and you still think that maybe "wet-end chemistry" might appeal to you as a possible focus of future graduate research. The first step is to let us know of your potential interests. You can call me at (919) 513-3022, send an E-Mail, or write to the address at the bottom of the Home Page.

Here's a short list of project areas in which we plan to start new work over then next several years. As a new graduate student it is highly likely that you will be assigned one of these topics, or something related. The specific topic will depend on various factors such as (a) your background and interests, (b) whether or not another student or students is already working on the project, (c) the funding schedule of the foundation or company that is supporting the work.

  1. Methods to monitor the state of charge of fiber surface. The goals of projecte in this area are two-fold. The short-term goal is to overcome technical barriers hinder progress in applying certain charge analysis methods to the monitoring and control of chemical additives on paper machines. The longer-term goal is to show how streaming current (piston type) and streaming potential (fiber-pad type) tests can be used to probe polyelectrolyte adsorption affinities. Funding has been awarded by the TAPPI Foundation for work in this area.
  2. Strategies to achieve retention, drainage, and good formation uniformity. Projects in this area will make use of experimental methods that have been developed at NC State for monitoring floc strength and floc size as a function of addition of papermaking chemicals and application of hydrodynamic shear. The work is likely to involve probing the mechanisms by which chemical additives work (charge effects, polymer bridging, micro-particle effects, etc.), and it is likely to also include some practical applications.
  3. Strategies for coping with the impacts of reduced fresh water use, high fines levels, and high levels of anionic colloids. One of the great advantages of tackling a project of this nature at NC State University is that the Department of Wood and Paper Science here has a lot of strength in the areas of pulping, bleaching, and recycling. Basically, we know a lot about different pulp furnish conditions. The challenge is to show how wet-end additives can be manipulated to overcome adverse effects of some of the materials present in those types of pulp supply.
  4. De-inking and its effects on the wet end. Support from an industrial consortium has allowed NCSU to conduct an aggressive program of research in the area of de-inking. A natural extension of this work will be to examine how various de-inking additives affect wet-end chemistry.

To get the official information about academic requirements for a Masters or Ph.D. degree, you need to go to the Graduate School's web-page or contact the Director of the Graduate Program at the Department of Wood and Paper Science (Dr. John Heitmann, 919-515-7711).

The "Educational Opportunities" section of this website lists some unofficial background information to give you a sense of the courses and other activities in the department. Should you decide to pursue graduate studies, either here or elsewhere, here are some things that you might consider:

Get to know your field: Students are expected to become experts within their topic area. That implies that they start a thorough literature search early in their project work. They need to be ready to present aspects of this knowledge in one or more seminars, in impromtu meetings with visitors, and ultimately in their thesis and publications.

Do quality research: In our wet-end chemistry program we rely very heavily on the results of laboratory experiments. As members of the scientific community we rely on careful technique, replication of results, and statistical tests to show that we have done enough tests with enough care in order to prove our points.

Originality: The product of work that we do together as members of the scientific community has to go well beyond what others may have done at another time and place. In other words, it has to be original. Usually this is not the biggest challenge, since there are many project areas where our understanding remains incomplete.

Analysis: Students are required to show how their data makes sense in light of (a) previous work, (b) theory, and (c) implications of the work in terms of future papermaking practices.

Publications: Students are expected to publish research articles, as appropriate, as a project unfolds. In fact, in some programs the final thesis may consist of an introductory section followed by a series of published articles. In most cases the student chooses to write a thesis and also publish articles. Publications are likely to involve joint authorship due to the fact that contributions of data, ideas, and writing will come from different members a group.

Length of stay: Because each student has to successfully defend a thesis, one cannot say for sure that "a Master of Science degree project takes two years and a Ph.D. project takes 3.5." Those could be gross estimates, in the case of a well-qualified student at a US University. The thesis committee overseeing each project has to judge whether the amount, quality, and originality adds up to a sufficiently significant body of work to merit a degree. As noted earlier, prospective students interested in academic requirements are urged to also look at the Graduate School web-page and ELSEWERE ON THIS WEBSITE.


North Carolina State is a "Research I" University, and as such is a leading center of graduate research. Our enrollment numbers are as follows:

M.S. Canditates: 15
Ph.D. Candidates: 10

Between 1988 and 1998 we granted 37 M.S. degrees and 21 Ph.D. degrees.

Funding for our graduate program (including tuition and stipends for the graduate students) has come from the following sources:

20% from McIntyre-Stennis grants
6% from industrial fellowship grants
42% from industrial research projects
32% from government research grants

Total funding is approximately $1,200,000 annually

As North Carolina's leading technological university, NC State ranks tenth in the U.S. for industry-sponsored research and development expenditures. In 1997 NC State attracted $400 million for research and extension activities. The NC State University library is among the country's top 50 university libraries. Faculty and students also work closely with leading edge corporations and research centers in nearby Research Triangle Park, including the Research Triangle Institute and North Carolina Biotechnology Center.


The Department of Wood and Paper Science is housed in a 100,000 square foot facility that includes well-equipped laboratories for paper testing, analytical chemistry, and biotechnology. A modern pilot plant with a fully automated paper machine, a pulping system for chemical and mechanical pulping, and a complete modular recycling system are available for use in research. In addition, graduate students have access to the university research support centers such as the NMR Center, the Microscopy Center, and the Mass Spectroscopy Center.

Opportunities for Research Partnerships: Corporate partners

Not all research projects either can or should be done at a university. But many companies find that university research can make good sense. Reasons to think seriously about sponsoring some research at a university (at NCSU, for example) are as follows:

Students who are developing the new technology can later be hired by the company. By that time people at the company already know the student well. They are in a good position to weigh the benefits of hiring someone who already is an expert in a specific area that may be critical to their future.

Projects that tend to work well

Some types of industrially sponsored research projects that have worked especially well in the past in a university setting include the following:

Projects that don't lend themselves well to a university setting

Although many of the research needs of a company could be achieved at a university, there are a few types of research that may be best done "in-house." For example, "Company A" is unlikely to fund graduate student research if their aim is to develop unpatented trade secrets that remain hidden from "Company B." The reason has little to do with the ability or lack of ability of students and faculty to keep secrets. Rather, by law, significant results from university projects carried out by students must be made available for publication. (Note that reports can be written in a way that also respects the secrecy of confidential information obtained from outside of the university.)

Motivating factors for research

Over time, two factors have tended to dominate the nature of research work carried out in groups such as NC State University's Department of Wood and Paper Science:

1. Research interests and areas of curiosity of the faculty and graduate students

2. What gets funded

The dynamic tension between ideas and money creates a rich environment for innovation. Purely pragmatic studies fail to generate interest at the university level, since they may not provide enough challenge to the student. On the other hand, ideas of no potential economic merit may fail to attract grant or fellowship support. Surviving projects (when the process works) tend to be those which have the potential to be both fun and profitable.

Potential corporate-sponsored research projects in the field of wet-end chemistry

If your company has some research needs in the area of wet-end chemistry, please consider the following three-step process:

1. The company visits NC State (and other schools), reviews our capabilities, and outlines an area of technology in which there is a critical need to find out "how something works" or "how it can work better."

2. One or more of our staff submits a brief research proposal and budget.

3. After negotiation and fine tuning (if necessary) the proposal is accepted.

Some areas in which we especially would welcome corporate support include the following:

Efforts to improve the performance of retention and drainage aids in the presence of high levels of interfering substances, fines, and/or salts
Technologies dependent on increasing the reliability of electrokinetic tests such as colloidal charge titrations by streaming current and related methods
Development of chemical strategies to achieve more uniform formation and optimized sheet structure
Projects involving addition of wet-end additives to fiber furnish that has been subjected to different pulping, bleaching, or recycling operations
Assessment of the strength and relative size of fiber flocs as a function of chemical treatments and hydrodynamic shear


These ideas are just a few examples. Possibly you have a completely different idea that also may fit in well with our overall projects at NC State. The first step is to let us know. You're welcome to come and visit. Also, we can come out and visit you and your people. Call me at (919) 513-3022 or send me an E-Mail.

Emerging Technology Emerging technologies

The following is a list of recent publications related to our research work in the Department of Wood and Paper Science at North Carolina State University. A separate page gives Abstracts for all of the publications by Martin Hubbe and co-authors.


Articles 2001 and earlier:

Zhang, M., Hubbe, M. A., Venditti, R. A., and Heitmann, J. A., "Effect of Chemical Pretreatments of Never-Dried Pulp on the Strength of Recycled Linerboard," Proc. TAPPI Papermakers Conf., 2001.

Zhang, M., Hubbe, M. A., Venditti, R. A., and Heitmann, J. A., "Can Recycled Kraft Fibers Benefit from Chemical Addition Before They Are First Dried?," APPITA J., in preparation.

Wang, F., and Hubbe, M. A., "Development and Evaluation of an Automated Streaming Potential Measurement Device," Colloids and Surfaces A, in preparation.

Wang, F., and Hubbe, M. A., "Charge Properties of Fibers in the Paper Mill Environment. 1. Effect of Electrical Conductivity," J. Pulp Paper Science, submitted.

Chen, J., Hubbe, M. A., and Heitmann, J. A., "Measurement of Colloidal Charge in the Paper Mill by Streaming Current," Proc. TAPPI Papermakers Conf., 2001.

Hubbe, M. A., and Wang, F., "Where to Add Retention Aid: Issues of Time and Shear," Proc. TAPPI Papermakers Conf., 2001.

Hubbe, M. A., "Reversibility of Polymer-Induced Fiber Flocculation by Shear. 1. Experimental Methods" Nordic Pulp and Paper Research Journal, in press; presentation at International Paper Coating Chemistry Symposium, June 6-8, 2000

Hubbe, M. A., "Reversibility of Polymer-Induced Fiber Flocculation by Shear. 2. Multicomponent Chemical Treatments" Nordic Pulp and Paper Research Journal, in preparation.

Wang, F., Tanaka, H., Kitaoka, T., and Hubbe, M. A., "Distribution Characteristics of Rosin Size and their Effect on the Internal Sizing of Paper," Nordic Pulp and Paper Research Journal, in press; presentation at International Paper Coating Chemistry Symposium, June 6-8, 2000

Hubbe, M. A., "Selecting and Interpreting Colloidal Charge Measurements," Proc. Scientific and Technical Advances in Wet End Chemistry, PIRA, Barcelona, June 19-20, 2000.

Zhang, M., Hubbe, M. A., Venditti, R. A., and Heitmann, J. A., "Loss of bonding Strength Dye to Drying and Repulping of Kraft Fibers: Effects of Chemical Additives," Proc. International Symposium on Environmentally Friendly and Emerging Technologies for a Sustainable Pulp and Paper Industry, Taipei, Taiwan, April 25-27, 2000.

Chen, J., Hubbe, M. A., Heitmann, J. A., and Chang, H.-M., "The Effect of Paper Additives on Agglomeration During the Recycling Process," Proc. International Symposium on Environmentally Friendly and Emerging Technologies for a Sustainable Pulp and Paper Industry, Taipei, Taiwan, April 25-27, 2000.

Hubbe, M. A., U.S. Patent 5,936,151, Aug. 10, 1999, "Method and Apparatus for Measuring an Electrical Property of Papermaking Furnish."

Hubbe, M. A., Wagle, D. G., and Ruckel, E. R., U.S. Patent 5,958,180, Sept. 28, 1999, "Method for Increasing the Strength of a Paper of Paperboard Product."

Hubbe, M. A., "Difficult Furnishes," Proc. TAPPI '99, 1353-1367; literature review and a proposal to broaden the view of what types of paper furnish components need to be considered in relationship to runnability and product quality.

Hubbe, M. A., "Paper: Wetting and Penetration of Liquids into," Encyclopedia of Materials Technologies, Elsevier; Chapter solicited by subject editor.

The following items are brief descriptions of new knowledge and research tools that have been developed recently in our wet-end chemistry program.

Recent Results of Wet-End Chemistry Research:

1. Bench-scale analysis of fiber floc strength. We have achieved reproducible measurements of the strength of fiber flocs present in a beaker at consistencies similar to those found in a headbox. By this means we have been able to monitor floc strength as a function of a range of wet-end chemical additives, orders of addition, and effects of hydrodynamic shear. The results have led us to a new understanding of how flocculating agents can be employed on a paper machine, to obtain benefits in retention and drainage, while still minimizing any significant adverse effect on product uniformity.

2. Convenient, on-line analysis of fiber floc relative size. In a related development, by working with an instrument vendor we have developed a way to continuously monitor the relative size of fiber flocs in a clear plastic tube. Remarkably, there are clear systematic differences between results from the dynamic floc size tests, relative to the floc strength tests mentioned above. The dynamic tests do not appear to be affected by the weak associations (i.e. "soft flocs") that can cause formation of networks of fibers in quiescent fiber slurry under suitable conditions of treatment.

3. Characterizing the loss of bonding potential due to the initial drying of unbleached kraft pulps. Min Zhang in our department has developed a series of procedures to evaluate changes in virgin unbleached kraft pulp. Dried pulp that is subsequently reslurried and formed into a second generation of handsheets was found to yield substantially lower compression strength and other strength properties related to inter-fiber bonding. The loss of bonding strength is accompanied, in a consistent way, by a loss in water-holding capacity (WRV) of the fibers. We have received a grant from the Department of Energy (DOE) through the American Forest and Paper Association's Agenda 2020 program that will allow us to continue this work and evaluate strategies to overcome this phenomenon.

4. Recycling projects. There is a close relationship between many issues of paper recycling and wet-end chemistry. Several graduate students in the department are engaged in studies aimed at improving the separation of toner, wax, and sticky particles from secondary fibers. As one example, research has shown unexpected effect of certain wet-end additives on subsequent efforts to "de-ink" xerographic copy paper. Certain chemical components that are used during paper production appear to stabilize the toner, making it resistant to agglomeration and subsequent removal by filtration. Results have been correlated to differences in the electrophoretic mobilities of the toner particles.

5. Uses of enzymes. Work within the department was among the first to clearly show benefits of addition of enzymes to fiber furnish having excessively low freeness. Treatment yielded improved drainage and favorable strength characteristics. Further work has elucidated the effects of lignin on the enzymatic effects, as well as the use of enzymes in preparation of dissolving pulps.

6. Tissue creping forces. Monish Desai, a graduate student within our department, is using a specialized device to detect how wet-end chemical conditions affect the detachment force of tissue from a Yankee cylinder under simulated production conditions.

7. Streaming current test procedures. Conventional streaming current analysis has been found useful under favorable conditions as a means of monitoring or controlling the level of colloidal charge in paper machine process water. We are pursuing an alternative approach of using the streaming current probe surfaces to model the interaction of wet-end chemicals with hydrophobic materials such as xerographic toners. Graduate student Junhua Chen is doing work in this area with funding from the TAPPI Foundation.

8. Charge testing at high levels of electrical conductivity. A post-doctoral Research Associate, Fei Wang, is working to develop a new charge analysis test that is better suited to facilities that recycle fiber and reuse most of their water many times. Such practices can lead to an enrichment of salts. Electrical conductivities higher than about 1 mS/cm begin to interfere with conventional methods of analysis of colloidal charge (e.g. colorimetric tests, streaming current titrations, micro-electrophoresis.

9. Reversibility of flocculation. It has become well accepted that instances of so-called "bridging" flocculation yield strong fiber-to-fiber bonds, but that such bonds break down irreversibly when subjected to high levels of hydrodynamic shear. By contrast, it has been understood that charge-related flocculation mechanisms are relatively unaffected by shear. These assumptions now have been retested under conditions of very high shear, making it certain that all of the original fiber-to-fiber bonds were broken. Results shows a surprising divergence between the effects of prior chemical treatments on drainage rates versus retention efficiency after the furnish was exposed to the high shear. The results are consistent with a model in which shear forces that are sufficient to separate fibers from each other are still insufficient to detach certain fine particles from the fiber surfaces in the presence of suitable flocculants.

If any of these research topics stimulate your curiosity or interest, please get in touch. Or better yet, take time to visit us the next time that you are in the "Triangle" area of Raleigh, Durham, and Chapel Hill, North Carolina.

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