REPORTS c

January, August & Final Reports

.

.

Part

1

- ^Summa y Details REPORTS

Please use your TAB key to complete part 1 b 2.

CRDC Project Number:

January Report: Due 29-Jan-01

f c

August Report: Due 03-Aug-01

Final Report: Due within 3 months of project completion

Proiect Title: A Survev of Cotton Wax Contents in Australian Cotton

Project Commencement Date: 06/01 Project Completion Date: 07/02 Research Program: Processing and Market

Part 2 - Contact Details

Administrator: Mr Hayden Smith

Organisation: CSIRO Textile and Fibre Technology Postal Address: PO Box 21, Belmont, VIC 3216

Ph: 03 5246 4000 Fx: 03 5246 4057 E-mail: hayden.smith@csiro.au

Principal Researcher: Dr. Stuart Gordon

Organisation: CSIRO Textile and Fibre Technology Postal Address: PO Box 21, Belmont, VIC 3216

Ph: 03 5246 4000 Fx: 03 5246 4057 E-mail: stuart.gordon@csiro.au

Supervisor: (Name & position of senior scientist overseeing the project).

Organisation:

Postal Address:

Ph: Fx: E-mail:

Researcher 2 Drs. D. E. Evans and J. C. Church Organisation: CSIRO Textile and Fibre Technology Postal Address: PO Box 21, Belmont, VIC 3216

Ph: 03 5246 4000 Fx: 03 5246 4057 E-mail: david.evans@csiro.au

Signature of Research Provider Representative:

Part 3 - Tanuaru

b

Aumst Revort Format

(Maximum four pages)

1. What were your major project objectives for the past year? (Please list).

2. Which of these objectives have been achieved?

3. How has your research addressed The Corporations three outputs:

Sustainability of natural resources, profitability and competitiveness, andlor people and communities?

4. Which objectives were not achieved and why? (Please provide detail of any problems you have had during the year).

5. What are your specific project objectives for the coming financial year?

6. What aspects of your research project do you envisage having problems with in the coming year and why?

NOTE: This question is aimed at identifying areas in which CRDC may be able to implement assistance to help avoid potential problems.

7. To what extent have your research results to date been disseminated to other researchers growers or the industry?

8. Will your research results be useful to other researcherslgrowerslindustry in the next year and if so how do you intend to communicate these results or

9. Were there major highlights in your work over the last six months? Please give a brief outline.

10. Are changes to the Intellectual Property register required?

You may also submit a separate confidential report of information, which should be included in the report but which you reasonably consider is confidential information.

Pnrt

4 -

Project V ~ w i n t i o ~ r s f o u Jnirrrary Report

. . . -. .. . .. . -.

Detail and justify any variations to the original project proposal that you anticipate for the coming financial year (July to June).

(E2 V a r i a t i o ~ x to outcomes o r objcciives, project timeline, budgets, or personnel).

Part

3

- Final Reaovt Format

1. Outline the background to the project.

Cotton wax is essential for the efficient processing of cotton fibre into spun yarn.

It provides a lubricating layer that reduces fibre-to-metal friction and therefore fibre breakage during mechanical processing. The downside is that this layer also acts as an impermeable barrier to the entry of water and dye molecules into the fibre. For successful, even dyeing - this barrier must be removed by scouring and/or bleaching.

The percentage of wax on commercial cottons generally varies between 0.3% and

1.0% on the weight of fibre when extracted with non-polar solvents. The

chemical composition of the wax is complex and contains a number of lipid classes including wax alkanes, fatty acids, fatty alcohols, plant steroids and mono, di and triglycerides. Most of the wax resides on the surface of the fibre and impregnated in the primary wall, although some remains in the secondary wall of the fibre even after extensive soxhlet extraction.

During the early 1990s, the Cotton Research and Development Corporation (CRDC) commissioned fibre-to-fabric trials to examine the effect of plant variety upon spinning ability, yarn properties and dye uptake variability. While the trials found that variation in dye uptake was due predominantly to a

combination of fibre maturity and fineness (linear density), which are largely environmental effects, it was strongly suspected that the cotton wax on some varieties had an effect upon dye uptake, due to the wax on some varieties being more difficult to remove than others.

The issue of the wax content of Australian cottons has been raised in more recent times by local and international dyers and finishers alike, and from spinners of Australian cotton who sell yarn into knitting markets. It's a particularly vexing issue, especially as it relates to how the wax levels of varying Australian cotton plants contribute to dye uptake variability - most notably in fabrics that undergo limited preparation before dyeing.

The costs to dyers and finishers can be counted in terms of product claims, e.g., fabric returned from a customer due to uneven dyeing, and/or the cost of

implementing costly scour procedures before bleaching to ensure the removal of wax and consistent dye uptake is achieved.

2. List the project objectives and the extent to which these have been achieved.

1. To continue a survey started in 2000/01 and further define the wax contents of Australian cotton varieties grown in different regions using various solvent extraction techniques.

2. Using analytical techniques such as thin layer chromatography and chemical spectroscopy define the chemical differences between extracted waxes found on Australian varieties grown in different regions.

3. Discuss results with industry and recommend changes to preparation (scouring and bleaching) recipes to eliminate dye uptake differences due to wax types and levels.

Achievement of the first two objectives revealed a wide range in the amount of wax on Australian cotton varieties although the chemical differences between the waxes extracted were small. The exception to this was for cottons that had been water or heat stressed. These cottons had low micronaire values and high concentrations of long chain hydrocarbon waxes. It is important to note that not all low micronaire cotton had these high concentrations of hydrocarbon waxes although low micronaire cotton by virtue of its higher specific surface area had larger amounts of wax as a percentage of fibre weight.

A Melbourne dyer supplied the project with greige and bleached fabric. Extracts from these samples showed that most of the wax was removed although a small amount remained. Four bleaching recipes were tested and the amount of wax remaining after each was similar. The chemical make-up of the 'bleached' extract was difficult to determine due to the chemical reaction between the wax and the oxidizing agents in the bleach.

The hypothesis that these long chain hydrocarbon waxes are a cause of dye variability problems in Australian cotton was not tested in this study. The finding that cotton produces higher concentrations of hydrocarbon waxes when heat or water stressed needs to be properly tested using a fibre-to-fabric approach with plants that have been grown under controlled but stressful conditions. Until the environmental influences that cause the plant to produce more hydrocarbon waxes are revealed managing the textile outcome in a commercial dye house will be difficult.

3. How has your research addressed the Corporations three outputs:

Sustainability, profitability and international competitiveness, andlor people and community?

The aim of this study was to provide scientific evidence that to the complaint that the dye uptake in Australian cottons is variable due to different wax contents.

The study showed that wax levels and contents in Australian cottons are not genetically determined but vary depending upon environmental conditions. The environmental factors affecting the amount of wax are unknown, although it was found that heat and water stressed cottons had higher concentrations of hydrocarbon waxes.

Greater knowledge of Australian cotton fibre properties including waxes enhances the profitability and international competitiveness of the Australian crop.

4. Detail the methodology and justify the methodology used.

A report detailing and justifying the methodology used in this project will be forwarded to the CRDC before October 31" 2002.

5. Detail results including t h e statistical analysis o f results.

A report detailing and justifying the statistical analyses used i n this project will b e forwarded to the CRDC before October 31" 2002.

6. Discuss t h e results, and include a n analysis o f research o u t c o m e s compared w i t h objectives.

T h e following discussion represents only a brief discussion o f the m a i n conclusions. A report detailing results f r o m the entire project will be forwarded t o the CRDC before October 31" 2002.

T h e percent ( o n weight o f fibre) extractable w a x ( % E W ) results s h o w that a w i d e range o f w a x contents that can b e found o n one particular variety. Statistically, t h e differences i n w a x contents b e t w e e n most o f the regions w e r e significant and point to environmental e f f e c t s as being v e r y important i n governing the amount o f w a x laid d o w n . T h e influence o f the environment o n micronaire also means that there is o f t e n a relationship between %EW and micronaire. Although not evident i n this subset o f the surveyed samples, it i s usual to expect that micronaire varies inversely w i t h the %EW.

In general, w a x extracts f r o m t h e samples tested i n t h e project had the same n u m b e r and amounts o f chemical components w i t h o n l y subtle changes across the samples analysed. These results are consistent w i t h previous w o r k showing t h e presence o f the same lipid classes i n similar proportions i n waxes f r o m a variety o f cotton cultivars, growths and species.

T h e exception t o the above generalisation was that t h e w a x f r o m some l o w micronaire cottons had m u c h higher concentrations o f hydrocarbon wax. Bees w a x is an example o f a hydrocarbon wax. These lipids are large, long chain molecules (> 16 carbon atoms) that are hydrophobic and can only b e removed w i t h organic solvents.

It w a s noted that the above relationship between l o w micronaire and higher concentrations o f hydrocarbon w a x did not occur for all l o w micronaire cottons examined i n this study. T h e relationship only manifested w h e n cotton plants (trial plots) had suffered heat or water stress during g r o w t h and consequently also had a l o w micronaire value. It was under these conditions that a higher proportion o f hydrocarbon w a x compared to cotton g r o w n under normal growth conditions w a s seen.

Further work is required to fully explain the e f f e c t seen i n the Brookstead sample. Based o n the findings o f this work, a more rigorously controlled growing trial, where the cotton is stressed during growth, is required to properly elucidate the plant mechanisms that result i n producing the high concentrations o f hydrocarbon waxes.

7. Provide an assessment of the likely impact of the results and conclusions of the research project for the cotton industry. Where possible include a statement of the costs and potential benefits to the Australian cotton industry and future research needs.

Until the environmental influences that cause the plant to produce more hydrocarbon waxes are revealed measuring and managing the textile impacts in a commercial dye house will be difficult. Ideally, the industry would fund further work so that the environmental effects leading to the 'stressed' cotton and the production of higher concntrations of hydrocarbon waxes can be properly ascertained.

8. Describe the project technology (eg. commercially significant developments, patents applied for or granted licenses etc).

9. Provide a technical summary of any other information developed as part of the research project. Include discoveries in methodology, equipment design, etc.

A report detailing the adaptation and advancement of standard methodology used in this project will be forwarded to the CRDC before October 31" 2002.

10. Detail a plan for the activities or other steps that may be taken;

(a) to further develop or to exploit the project technology.

A proposal will be submitted to the CRDC in January 2003 with details of a aimed at proving the hypothesis that long chain hydrocarbon waxes are a cause of dye variability problems in Australian cotton. This hypothesis was not tested in this study. The finding that cotton produces higher concentrations of hydrocarbon waxes when heat or water stressed needs to be properly tested using a fibre-to-fabric approach with plants that have been grown under controlled but stressful conditions.

(b) for the future presentation and dissemination of the project outcomes.

The attached 'Plain English Summary' has been written for publication in the September edition of the Australian Cotton Grower Journal.

11. List the publications arising from the research project.

As above.

12. Are changes to the Intellectual Property register required?

N A

Part

4

-Final Report Plain English Szimma y

_-

l'rovide a half to onc: pagc Plain English S ~ i r n ~ n a r v of your research that is not commcrrcial in conficicncc-i, a n d that can he publisiic!d on ihc World Wide Web.

A longstanding issue facing the cotton industry is the e f f e c t that w a x levels can have o n everything f r o m spinning ability, yarn properties and ultimately, to d y e uptake.

Cotton w a x is essential for the efficient processing of cotton fibre into s p u n yarn. It provides a lubricating layer that reduces fibre-to-metal friction and therefore fibre breakage during mechanical processing. T h e downside is that this layer also acts as a n impermeable barrier to the entry o f water and d y e molecules into the fibre. For successful, e v e n dyeing - this barrier m u s t b e removed b y scouring a n d / o r

bleaching.

T h e percentage of w a x o n commercial cottons generally varies between 0.3% and 1.0% o n the weight o f fibre w h e n extracted w i t h non-polar solvents.

T h e chemical composition of the w a x i s complex and contains a n u m b e r o f lipid classes including w a x alkanes, fatty acids, fatty alcohols, plant steroids and m o n o , di and triglycerides. Most o f the w a x resides o n the surface o f the fibre and

impregnated i n t h e primary wall, although some remains i n the secondary wall o f the fibre e v e n after extensive soxhlet extraction [ l ] .

During the early 1990s, the Cotton Research and Development Corporation (CRDC) commissioned fibre-to-fabric trials to examine the e f f e c t of plant variety u p o n spinning ability, yarn properties and d y e uptake variability. W h i l e t h e trials found that variation i n d y e uptake w a s d u e predominantly t o a combination o f fibre maturity and fineness (linear density), w h i c h are largely environmental effects, it was strongly suspected that t h e cotton w a x o n some varieties had an e f f e c t u p o n d y e uptake, d u e to the w a x on some varieties being more difficult to remove than others.

T h e issue o f the w a x content o f Australian cottons has been raised i n more recent times b y local and international dyers and finishers alike, and f r o m spinners o f Australian cotton w h o sell yarn into knitting markets. It's a particularly vexing issue, especially as it relates t o h o w t h e w a x levels o f varying Australian cotton plants contribute to d y e uptake variability - most notably i n fabrics that undergo limited preparation before dyeing.

T h e costs to dyers and finishers can b e counted i n terms o f product claims, e.g., fabric returned f r o m a customer d u e to uneven dyeing, a n d / o r the cost o f implementing costly scour procedures before bleaching to ensure t h e removal o f w a x and consistent d y e uptake is achieved.

In a survey sponsored b y the CRDC and CSIRO Textile and Fibre Technology (CTFT) and conducted during the last year b y CTFT, the w a x extracts o f cotton fibre

samples gathered f r o m the Cotton Seed Distributor's 2000/01 variety trials were examined. Both the amount and t y p e o f w a x e s present o n the cottons were examined during t h e survey.

T h e percent (on w e i g h t o f fibre) extractable w a x ( % E W ) results for Sicala 40 g r o w n across 13 d i f f e r e n t sites together w i t h micronaire values is s h o w n i n Table l . T h e data illustrates t h e w i d e range of w a x contents that can b e found on one particular variety. Statistically, t h e differences i n w a x contents between most o f the regions are significant and point t o environmental e f f e c t s as being v e r y important i n governing the a m o u n t of w a x laid d o w n . T h e influence o f t h e environment on micronaire also means that there i s o f t e n a relationship b e t w e e n %EW and micronaire. A l t h o u g h not evident i n this subset of the surveyed samples, it is usual to expect that micronaire varies inversely w i t h the %EW [2,3 & 41.

Table 1 - W a x Contents o f Sicala 40 (CSD trials 2000/01)

/

^Varietv

[ [

l

^Region

1

^Trangie

1

^0.92

1

^4.4

1

Sicala 40

I I

Mt. Foster

/

0.94

I

4.4

1

Hillston Tandou

l I I

Walgett 0.56 4.3

/

Collarenebri

I

^{0.70 4.5}

0.33

I

Brookstead

I

^0.55

/

Boggabilla

1

^{1.03 4.4}

4.6 0.57

3.8 4.6 4.3 Hebel

4.4

0.54

I I

St. George

I

^0.58

1

^4.4

I

(

Dirranbandi

1

^0.63

In general, w a x extracts f r o m samples like those i n Table 1 had the same n u m b e r and amounts o f chemical components w i t h only subtle changes across t h e samples analysed. T h e s e results are consistent w i t h previous w o r k showing t h e presence of the same lipid classes i n similar proportions i n waxes f r o m a variety o f cotton cultivars, growths and species [5,6].

Moree

4.4

T h e exception t o the above generalisation was that the w a x f r o m s o m e l o w micronaire cottons had m u c h higher concentrations o f hydrocarbon w a x . Bees w a x is a n example of a hydrocarbon wax. These lipids are large, long chain molecules (>

16 carbon atoms) that are hydrophobic and can only b e removed w i t h organic solvents. Figure 1 shows a high performance thin layer chromatogram (HPTLC) o f

0.61

Dalbv 0.99 4.4

the wax from the Brookstead (micronaire value of 3.8) sample together with a typical wax from the same cotton variety grown at Walgett (micronaire value of 4.3). The higher concentration of the hydrocarbon wax is readily apparent although other components in the two samples are comparable.

It was noted that the above relationship between low micronaire and higher concentrations of hydrocarbon wax did not occur for all low micronaire (micronaire values < 3.8) cottons examined in this study. The relationship only manifested when cotton plants (trial plots) had suffered heat or water stress during growth and consequently also had a low micronaire value. It was under these conditions that a higher proportion of hydrocarbon wax compared to cotton grown under normal growth conditions was seen.

Further work is required to fully explain the effect seen in the Brookstead sample.

Based on the findings of this work, a more rigorously controlled growing trial, where the cotton is stressed during growth, is required to properly elucidate the plant mechanisms that result in producing the high concentrations of hydrocarbon waxes.

Figure 1 - HPTLC of cotton wax extracted from two samples of Sicala 40 cotton. The dark stains at the top of lanes 1 & 2 (Brookstead) indicate the higher concentration of hydrocarbon waxes. Lanes 4 & 5 (Walgett) show a typical chromatogram of cotton wax and lane 3 shows a chromatogram of lipid standards.

References

1. Kling, A., and Hofstetter, H.H., Lipids in Cotton, Seqen-Oele-Fette- Wnchse, 92, 323-329 (1966).

2. Marsh, P. B., Barker, H. D., Kerr, T. and Butler, M. L., Wax Content as Related to Surface Area of Cotton Fibers, Textile Research Journal, 20,288 ^- 296 (1950).

3. Cordon, S. G., Unpublished work (2001).

4. Cui, X.L., Price, J.B., Calamari, T. A. and Hemstreet, J. M., Cotton Wax and its Relationship with Fibre and Yarn Properties, Part I: Wax Content and Fibre Properties, Textile Research Jot~rnal, 72,399 - 404 (2002).

5. Fargher, R.G., and Higginbotham, L., Constituents of Wax from Egyptian Sakellarides Cotton, J. Text. Instit, 419,419-433T (1924).

6. Hornoff, Gunther v. and Richter,H., Chemical Composition of Cotton Fibres Originating from various Areas, Fasterforsch. Textiletech., 15,165-177 (1964).

Part 5 - Janua y Supervisor Report (Scholarships Only) -

Tiie Scl.lolarsliip Recipiei-11's S~ipervisor is Lo provicl? a brief statcrnenl- on lhe liecipient's progress and achiwemt~iits during the i.elcvnnt year arid whcthcr the:

IRccipic!til is fulfilling Lhc roquirer~icnts of [lie posigraci~iatc o v unclcrgraduak ^caul-sc in wliich the Recipient is ci~rolied.